WO1999013075A2 - Human genes regulated by human cytomegalovirus and interferon - Google Patents

Abstract

This invention describes 23 genes related to HCMV infection. We demonstrate that 19 out of the 23 genes are induced by HCMV infection and that 6 of these genes were previously unidentified in public sequence data bases. We also show for the first time that 7 out of the 19 genes are also interferon-inducible. We demonstrate that 4 out of the 23 genes are repressed by HCMV infection. Two of these are known genes and the cDNA sequence that we have determined for the other two are not present in public data bases. The invention relates to using these genes as markers in assays screening for compounds that reverse the expression pattern of said genes following challenge with either cytomegalovirus or interferon. The invention further relates to anti-viral pharmaceutical compositions encompassing recombinant proteins, antibodies, antisense technology and gene therapy.

Description

HUMAN GENES REGULATED BY HUMAN CYTOMEGALOVIRUS AND

INTERFERON

TECHNICAL FIELD OF THE INVENTION The present invention relates to the identification of genes in which their expression is either induced or repressed upon either cytomegalovirus infection or interferon treatment. The invention also relates to using these genes as markers in assays screening for compounds that reverse the expression pattern of said genes following challenge with either cytomegalovirus or interferon. The invention further relates to anti-viral pharmaceutical compositions enncompassing recombinant proteins, antibodies, antisense technology, and gene therapy.

BACKGROUND OF THE INVENTION Human cytomegalovirus (HCMV) is a wide-spread human pathogen that causes birth defects and can be life-threatening to people whose immune system is compromised (AIDS and transplant patients). HCMV can alter gene expression through multiple pathways. For example, the virion gB and gH glycoproteins induce cellular transcription factors when they interact with their cell surface targets (1). Virion proteins, such as pp71 (2-4), can activate transcription (5); and viral proteins synthesized after infection, such as IE1 and IE2, regulate expression from a variety of promoters (6-10). Further, HCMV infection has been shown to perturb cell cycle progression (11-14), which leads to changes in gene expression.

Viral factors, induced cellular factors and changes in cell cycle progression have the potential to exert profound effects on gene expression, but relatively few cellular genes have been identified whose activity changes after HCMV infection (15). A more global understanding of HCMV-induced changes in cellular gene expression should help us to better understand how the virus interacts with its host cell during the replication process, and might direct us to new targets for therapeutic intervention in HCMV disease.

SUMMARY OF THE INVENTION In accordance with the present invention, certain novel cDNA sequences have been identified that originate from mRNAs that are expressed in response to HCMV infection. Therefore, the genes that encode these mRNAs are termed HCMV mducible genes {cig). Interestingly, and as set forth herein, these genes were also found to be inducible by interferon-α.

Accordingly, 19 genes that are induced upon HCMV infection of human cells and 4 genes that are repressed by HCMV infection of human cells have been identified. Further, the present invention reveals that the genes which are induced by HCMV infection are also induced by interferon-α . Finally, the 19 genes that are induced by HCMV and interferon-α include 6 genes that have not been reported previously.

Also in accordance with the present invention, certain novel cDNA sequences have been identified that originate from mRNAs that are repressed in response to HCMV infection. Therefore, the genes that encode these mRNAs are termed HCMV repressable genes {erg).

In one embodiment of the invention, the cigs can be used as markers for use in a screening assay to identify compounds that prevent the expression of any of these genes. Likewise, the ergs can also be used as markers for use in a screening assay to identify compounds that relieve the repression of these genes.

In a further embodiment, the screening assays also extend to use of antibodies against the proteins encoded by the above-mentioned cDNAs in an ELISA-type assay. In a yet a further embodiment, the screening assays can also be used to follow the efficacy of various treatment regimens in patients, thus leading to more effective treatment.

The present invention also extends to therapeutic applications utilizing the nucleotide sequences derived from the cigs and ergs in antisense therapeutics and gene therapy.

In a further aspect, the encoded proteins that can be infered from the cDNA sequences of the cigs and ergs can also be used in therapeutic applications. The fact that the cigs are also induced by interferon, combined with the fact that interferons are used in anti-viral therapy, gives strength to the notion that the proteins have potential as generic anti-viral compounds .

In yet a further aspect, one or more of the encoded proteins from the cigs may be responsible for the toxicity of interferon. Therefore, the newly discovered gene products have utility as targets for screens to discover compounds that could block this toxicity, thus leading to drugs that could greatly enhance the efficacy of interferon treatment by allowing the use of higher doses of interferon.

In a particular embodiment, the present invention relates to all members of the herein disclosed family of cigs and ergs.

The present invention also relates to a recombinant DNA molecule or cloned gene, or a degenerate variant thereof, which encodes any cig or erg gene product; preferably a nucleic acid molecule, in particular a recombinant DNA molecule or cloned gene, encoding the cig or erg gene product has a nucleotide sequence or is complementary to a DNA sequence contained in any of the cigs or ergs identified in the Sequence Listing as SEQ ID NOS. l, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21-26, 28, 30, 32, 34, 36, 38, and 39. The human and murine DNA sequences of the cigs and ergs of the present invention or portions thereof, may be prepared as probes to screen for complementary sequences and genomic clones in the same or alternate species. The present invention extends to probes so prepared that may be provided for screening cDNA and genomic libraries for the cigs and ergs. For example, the probes may be prepared with a variety of known vectors, such as the phage λ vector. The present invention also includes the preparation of plasmids including such vectors, and the use of the DNA sequences to construct vectors expressing antisense RNA or ribozymes which would attack the mRNAs of any or all of the DNA sequences set forth in the Sequence Listing (SEQ ID NOS. l, 3, 5, 7, 9, 11 , 13, 15, 17, 19, 21- 26, 28, 30, 32, 34, 36, 38, and 39). Correspondingly, the preparation of antisense RNA and ribozymes are included herein.

The present invention also includes cig or erg gene products {i. e. proteins) having the activities noted herein, and that contain amino acid sequences set forth in the Sequence Listing and selected from SEQ ID NOS:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 27, 29, 31, 33, 35, and 37.

In a further embodiment of the invention, the full DNA sequence of the recombinant DNA molecule or cloned gene so determined may be operatively linked to an expression control sequence which may be introduced into an appropriate host. The invention accordingly extends to unicellular hosts transformed with the cloned gene or recombinant DNA molecule comprising a DNA sequence encoding any one of the present cigs or ergs, and more particularly, the complete DNA sequence determined from the sequences set forth above and in SEQ ID NOS. l, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21-26, 28, 30, 32, 34, 36, 38, and 39.

According to other preferred features of certain preferred embodiments of the present invention, a recombinant expression system is provided to produce biologically active animal or human cig or erg gene products. The present invention naturally contemplates several means for preparation of the cig or erg genes and gene products, including as illustrated herein known recombinant techniques, and the invention is accordingly intended to cover such synthetic preparations within its scope. The isolation of the cDNA and amino acid sequences disclosed herein facilitates the reproduction of the cigs and ergs by such recombinant techniques, and accordingly, the invention extends to expression vectors prepared from the disclosed DNA sequences for expression in host systems by recombinant DNA techniques, and to the resulting transformed hosts.

The invention includes an assay system for screening of potential drugs effective to modulate cig or erg expression levels of target mammalian. In one instance, the test drug could be administered to a cellular sample, prior to or after HCMV-infection or interferon treatment, to determine its effect upon the cig or erg expression level to any chemical sample (including DNA), or to the test drug, by comparison with a control.

The assay system could be adapted to identify drugs or other entities that are capable of reducing the toxicity of interferon treatment by antagonizing one or more of the cigs. Such assay would be useful in the development of drugs that would allow for higher dosage interferon treatments without the concomitant toxicity normally associated with administering high levels of interferon.

In yet a further embodiment, the invention contemplates antagonists of the activity of a cig gene product. In particular, an agent or molecule that inhibits any cig gene product and, in turn, has antiviral activity in general and anti-HCMV activity in particular.

In still yet a further embodiment, the invention contemplates the use of a erg gene product as a therapeutic to treat HCMV infection. As infection with HCMV reduces the level of these gene products, it follows that replacement of this gene product, either through gene therapy or via direct administration of the gene product, has potential to alleviate HCMV infection and/or its associated symptoms.

The present invention extends to the development of antibodies against the cig or erg gene products, including naturally raised and recombinantly prepared antibodies. For example, the antibodies could be used to screen expression libraries to obtain the gene or genes that encode the cig or erg gene products. Such antibodies could include both polyclonal and monoclonal antibodies prepared by known genetic techniques, as well as bi-specific (chimeric) antibodies, and antibodies including other functionalities suiting them for additional diagnostic use conjunctive with their capability of modulating activities associated with the cig or erg gene products.

Thus, cig or erg gene products, their analogs and/or analogs, and any antagonists or antibodies that may be raised thereto, are capable of use in connection with various diagnostic techniques, including immunoassays, such as a radioimmunoassay, using for example, an antibody to the cig or erg gene products that has been labeled by either radioactive addition, or radioiodination.

In an immunoassay, a control quantity of the antagonists or antibodies thereto, or the like may be prepared and labeled with an enzyme, a specific binding partner and/or a radioactive element, and may then be introduced into a cellular sample. After the labeled material or its binding partner(s) has had an opportunity to react with sites within the sample, the resulting mass may be examined by known techniques, which may vary with the nature of the label attached.

In the instance where a radioactive label, such as the isotopes ³H, ^I4C, ³²P, ³³P, ³⁵S, ³⁶C1, ⁵¹Cr, ⁵⁷Co, ⁵⁸Co, ⁵⁹Fe, ⁹⁰Y, ^I25I, ¹³¹I, and ¹⁸⁶Re are used, known currently available counting procedures may be utilized. In the instance where the label is an enzyme, detection may be accomplished by any of the presently utilized colorimetric, spectrophotometric, fluorospectrophotometric, amperometric or gasometric techniques known in the art.

The present invention includes an assay system which may be prepared in the form of a test kit for the quantitative analysis of the extent of the presence of the cig or erg gene products (either mRNA or protein), or to identify drugs or other agents that may mimic or block their activity. The system or test kit may comprise a labeled component prepared by one of the radioactive and/or enzymatic techniques discussed herein, coupling a label to the cig or erg gene products, their agonists and/or antagonists, and one or more additional immunochemical reagents, at least one of which is a free or immobilized ligand, capable either of binding with the labeled component, its binding partner, one of the components to be determined or their binding partner(s).

In a further embodiment, the present invention relates to certain therapeutic methods which would be based upon either modulating expression levels cigs and/or ergs or antagonizing the activity of any of the cig gene products, their subunits, or active fragments thereof, or upon agents or other drugs determined to possess the same activity. A first therapeutic method is associated with the prevention of the manifestations of conditions causally related to or following from HCMV infection, and comprises administering an agent capable of modulating the production and/or activity of any of the cig or erg gene products, either individually or in mixture with each other in an amount effective to prevent the development of those conditions in the host. For example, drugs or other binding partners to the cig or erg gene products may be administered to inhibit or potentiate their activity, as it relates to HCMV or other viral infection.

Accordingly, it is a principal object of the present invention to provide cig or erg gene products in purified form that have utility in treating, or identifying drugs (compounds) to treat, HCMV or other viral infection. It is a further object of the present invention to provide antibodies to the cig or erg gene products, and methods for their preparation, including recombinant means.

It is a further object of the present invention to provide a method for detecting the presence of the cig or erg mRNA or protein gene products in mammals in which invasive, spontaneous, or idiopathic pathological states are suspected to be present.

It is a further object of the present invention to provide a method and associated assay system for screening substances such as drugs, agents and the like, potentially effective in either mimicking the activity or combating the adverse effects of the cig or erg gene products in mammals.

It is a still further object of the present invention to provide a method for the treatment of mammals to control the amount or activity of the cig or erg gene products, so as to alter the adverse consequences of such presence or activity, or where beneficial, to enhance such activity.

It is a still further object of the present invention to provide a method for the treatment of mammals to control the amount or activity of the cig or erg gene products, so as to treat or avert the adverse consequences of invasive, spontaneous or idiopathic pathological states.

It is a still further object of the present invention to provide pharmaceutical compositions for use in therapeutic methods which comprise or are based upon the cig or erg gene products, their binding partner(s), or upon agents or drugs that control the production, or that mimic or antagonize the activities of the cig or erg gene products. Other objects and advantages will become apparent to those skilled in the art from a review of the ensuing description which proceeds with reference to the following illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1. Characterization of UV-inactivated HCMV (UV HCMV). (A) Western blot showing that UV irradiation of the virus blocks expression of the HCMV IE1 and IE2 RNAs, but has no effect on the delivery of a virion protein to cells. HF cells were mock infected or infected, and extracts were prepared 8 or 21 h later. Lanes 1-6 were reacted with an antibody (MAbδlO) that binds to two immediate early proteins (IE1 and IE2), while lanes 7-9 were reacted with an antibody to a virion constituent, pp65. The molecular weights of marker proteins are indicated to the left of the panels. (B) Northern blot showing that IE1 RNA is detected at 8 h after infection of HF cells with HCMV but not after infection with UV HCMV. (C) Immunofluorescent localization of pp65 and IE1/2 within infected cells. HF cells were infected with for 2 or 8, reacted with antibody to pp65 or IE1/IE2 followed by a fluorescein-labeled secondary antibody and counterstained with ethidium homodimer-1.

FIGURE 2. Differential expression of RNAs in HF cells assayed by Northern blot. (A) RNA was prepared from mock- infected (M), HCMV-infected cells (C), or UV HCMV-infected cells and assayed using cloned cDNA segments. The different clones {cigs) are identified above the panels. (B) RNA was prepared from mock- infected (M), HCMV-infected (C) or HCMV-infected cells that were treated with cycloheximide (CX) and assayed as in panel A. (C) RNA was prepared from mock- infected cells (M), HCMV-infected cells (C) or cells treated with interferon-α (I) and assayed using probes corresponding to the cigz or the previously characterized, interferon-inducible mxA gene. (D) RNA was prepared as in panel A and assayed using probes corresponding to known interferon-inducible genes (mxA, isgl5K, IFN-b) or control genes that are not induced by interferon (p53, p21 , cPLA2, actin). FIGURE 3. The HCMV particle mediates the induction of differentially expressed HF RNAs. (A) Requirements for induction monitored by Northern blot assay. The relative amounts of three cellular RNAs ( ^'gl, cig6 and g49) were monitored in mock- infected cells (mock), HCMV strain AD169-infected cells (HCMV), medium from a virus stock from which HCMV particles were removed by filtration (inf. med.), mock-infected cells treated with 100 mg/ml cycloheximide (CX), HCMV strain AD169-infected cells treated with 100 mg/ml cycloheximide (CX+HCMV), cells infected with purified HCMV strain AD 169 particles (virions), cells infected with purified non-infectious enveloped particles from strain AD 169 (NIEPs), adenovirus-infected cells (Ad _i7309), herpes simplex type 1 -infected cells (HSV-1), HCMV strain Towne-infected cells, HCMV strain Toledo-infected cells, interferon- α-treated cells (IFN-α), and interferon added to medium and passed through the filter to exclude virus (fil. IFN-α). (B) Northern blot assay demonstrating that antibody which neutralizes HCMV (antibody C) blocks the induction of cig RNA accumulation, while antibodies that neutralize interferon-α or β (antibody Iα, Iβ) block the induction of cig RNAs by interferon-α or β (inducer Iα, Iβ) but have no effect on the induction of cig RNAs by HCMV (C). RNA prepared from mock- infected control cells is designated M. The cellular cytosolic phospholipase A2 RNA that is not modulated by infection or interferon treatment is assayed at the bottom of the figure as a loading control (control, cPLA2).

FIGURE 4. Requirements for the induction of cig RNA accumulation. (A) An intact HCMV particle is required. Purified HCMV particles were treated with a mixture of TritonXlOO and DOC (T/C) and separated by centrifugation into supernatant (S) and pellet (P) fractions. Northern blot assays show the effect of detergent treatment on the induction of two cig RNAs {cigl and g49) by virus particles (HCMV) or interferon-α (IFN-α). (B) The induction of cig RNAs does not invovle the release and subsequent action of mediators stores within infected HF cells. At 8 h after treatment, RNA was prepared from mock- infected cells (lane 1), HCMV-infected cells (lane 2), or a 9: 1 mixture of mock and infected cells (lanes 3 and 4). The two mixed cultures differed in the time after infection when the cells were mixed. In mixture 3, cells were mixed at 1 h after infection; in mixture 4, RNAs were prepared and mixed from 8 h mock- and HCMV-infected cells. RNAs were analyzed by Northern blot using cellular {cigl, cigβ, cig49, cPLA2) and viral (IE1) probes.

FIGURE 5. Kinetic analysis of cig RNA accumulation. HF cells were either mock- infected (M) or treated with the inducers identified to the right of each blot (HCMV, HSV-1, IFN-α), RNA was prepared at various times after treatment (indicated above lanes), and analyzed by Northern blot using the probes indicated to the left of each blot {cigl, cig49, HCMV IE1, HSV-1 icp47).

DETAILED DESCRIPTION As described in detail infra, differential display analysis was employed to identify mRNAs that accumulate to enhanced levels in human cytomegalovirus-infected as compared to mock- infected cells. RNAs were compared at 8 hours after infection of primary human fibroblasts. Fifty-seven partial cDNA clones were isolated, representing about 26 differentially expressed mRNAs. Eleven of the mRNAs were virus-coded and 15 were of cellular origin. Six of the partial cDNA sequences have not been reported previously. All of the cellular mRNAs identified in the screen are induced by interferon-α and β. The induction in virus-infected cells, however, does not involve the action of interferon or other small signalling molecules.

Neutralizing antibodies that block virus infection also block the induction. These RNAs accumulate after infection with virus that has been inactivated by treatment with UV light, indicating that the inducer is present in virions. From the above, it is concluded that human cytomegalovirus induces interferon-responsive mRNAs. In its broadest aspect, the invention describes 23 genes related to HCMV infection. These genes are described in the EXAMPLES. We show for the first time that 19 genes are induced by HCMV infection (see Table 1 in EXAMPLE 4); we identify 6/19 genes for the first time (these genes are listed as "new" in Table 1), i.e. , the partial cDNA sequences that we have derived are not found in public sequence data bases; 12/19 genes were previously shown to be induced by interferon, and we show for the first time that 7/19 genes are induced by interferon (the 6 genes listed as "new" in Table 1 as well as KIAA0062).

Since these genes are expressed at high level in HCMV-infected cells, it is possible that they are needed for successful replication and spread by the virus. Therefore, the genes have utility as targets for the development of screens to identify drugs that inhibit their expression or action. Inhibition of the normal activity of these HCMV- induced cellular gene products might inhibit HCMV replication and spread. It may also be possible to identify the viral gene product that causes the enhanced expression of these genes and discover a drug that blocks its function, thereby preventing accumulation of these cellular genes.

The 7 genes that are shown to be induced by interferon-α for the first time have additional utility. This is probably the most important aspect of the invention since interferon-related activities are not limited to the control of HCMV. Interferons alpha and beta exhibit many different functions, including: (1) the induction of an antiviral state; (2) inhibition of cell growth; (3) induction of class I MHC antigens; and (4) activation of macrophages, natural killer cells and cytotoxic T lymphocytes. Interferons can block the replication and spread of many different viruses, the growth of nonviral pathogens and the growth of certain cancer cells. Interferon functions by initiating a signaling cascade that results in the expression of inter feron-responsive gene products that then mediate interferon actions, such as antagonizing the growth of a virus (given this function of interferon, it is strange that HCMV induces interferon-response genes). The 7 newly identified gene products could exhibit subsets of the activities ascribed to interferons alpha and beta. Therefore, they have potential as therapeutic proteins. The utility of interferons as therapeutic agents is limited because they are toxic. Possibly one or more of these newly discovered interferon-response genes produces a product that is responsible for the toxicity (or a significant portion of the toxicity). If so, the newly discovered gene products have utility as targets for screens to discover drugs that could block aspects of their activity that leads to toxicity. Such drugs could greatly enhance the utility of interferons as therapeutics by reducing their toxicity and permitting higher doses.

We show for the first time 4 genes that are repressed by HCMV infection. Two of these are known genes and the cDNA sequence that we have determined for the other two are not present in public data bases. If their repression is important for HCMV replication and spread, then the delivery of these products as proteins or perhaps within an expression vector could interfere with HCMV replication and spread. It might also be possible to identify the viral gene product that is responsible for their repression and discover a drug that blocks its function.

In accordance with the present invention there may be employed conventional molecular biology, microbiology, and recombinant DNA techniques within the skill of the art. Such techniques are explained fully in the literature. See, e.g., Sambrook et al, "Molecular Cloning: A Laboratory Manual" (1989); "Current

Protocols in Molecular Biology" Volumes I-III [Ausubel, R. M. , ed. (1994)]; "Cell

Biology: A Laboratory Handbook" Volumes I-III [J. E. Celis, ed. (1994))];

"Current Protocols in Immunology" Volumes I-III [Coligan, J. E. , ed. (1994)];

"Oligonucleotide Synthesis" (M.J. Gait ed. 1984); "Nucleic Acid Hybridization" [B.D. Hames & S.J. Higgins eds. (1985)]; "Transcription And Translation" [B.D.

Hames & S.J. Higgins, eds. (1984)]; "Animal Cell Culture" [R.I. Freshney, ed.

(1986)]; "Immobilized Cells And Enzymes" [IRL Press, (1986)]; B. Perbal, "A

Practical Guide To Molecular Cloning" (1984). Therefore, if appearing herein, the following terms shall have the definitions set out below.

The term "cig" or "cigs" refers to HCMV-inducible genes.

The term "erg" or "ergs" refers to HCMV-repressable genes.

The nucleotide sequences of the cDNA molecules associated with the cigs and ergs is presented in the Sequence Listing (SEQ ID NOS: l , 3, 5, 7, 9, 11, 13, 15, 17, 19, 21-26, 28, 30, 32, 34, 36, 38, and 39).

The term "product" in "cig or erg gene product" , and varients thereof, can refer to either protein or mRNA.

The term "cig or erg gene product(s), " and any variants not specifically listed, as used throughout the present application and claims can refer to proteinaceous material including single or multiple proteins, and extends to those proteins having the amino acid sequence data described herein and presented in the Sequence Listing (SEQ ID NOS:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 27, 29, 31 , 33, 35, and 37), and the profile of activities set forth herein and in the Claims. Accordingly, proteins displaying substantially equivalent or altered activity are likewise contemplated. These modifications may be deliberate, for example, such as modifications obtained through site-directed mutagenesis, or may be accidental, such as those obtained through mutations in hosts that are producers of the complex or its named subunits..

The amino acid residues described herein are preferred to be in the "L" isomeric form. However, residues in the "D" isomeric form can be substituted for any L- amino acid residue, as long as the desired fuctional property of immunoglobulin- binding is retained by the polypeptide. NH₂ refers to the free amino group present at the amino terminus of a polypeptide. COOH refers to the free carboxy group present at the carboxy terminus of a polypeptide. In keeping with standard polypeptide nomenclature, J. Biol. Chem. , 243:3552-59 (1969), abbreviations for amino acid residues are shown in the following Table of Correspondence:

TABLE OF CORRESPONDENCE

SYMBOL AMINO ACID

1 -Letter 3 -Letter

Y Tyr tyrosine

G Gly glycine

F Phe phenylalanine

M Met methionine

A Ala alanine

S Ser serine

I He isoleucine

L Leu leucine

T Thr threonine

V Val valine

P Pro proline

K Lys lysine

H His histidine

Q Gin glutamine

E Glu glutamic acid

W Trp tryptophan

R Arg arginine

D Asp aspartic acid

N Asn asparagine

C Cys cysteine

It should be noted that all amino-acid residue sequences are represented herein by formulae whose left and right orientation is in the conventional direction of amino- terminus to carboxy-terminus. Furthermore, it should be noted that a dash at the beginning or end of an amino acid residue sequence indicates a peptide bond to a further sequence of one or more amino-acid residues. The above Table is presented to correlate the three-letter and one-letter notations which may appear alternately herein.

A "replicon" is any genetic element (e.g. , plasmid, chromosome, virus) that functions as an autonomous unit of DNA replication in vivo; i.e. , capable of replication under its own control.

A "vector" is a replicon, such as plasmid, phage or cosmid, to which another DNA segment may be attached so as to bring about the replication of the attached segment.

A "DNA molecule" refers to the polymeric form of deoxyribonucleotides (adenine, guanine, thymine, or cytosine) in its either single stranded form, or a double- stranded helix. This term refers only to the primary and secondary structure of the molecule, and does not limit it to any particular tertiary forms. Thus, this term includes double-stranded DNA found, inter alia, in linear DNA molecules (e.g. , restriction fragments), viruses, plasmids, and chromosomes. In discussing the structure of particular double-stranded DNA molecules, sequences may be described herein according to the normal convention of giving only the sequence in the 5 ' to 3' direction along the nontranscribed strand of DNA (i.e. , the strand having a sequence homologous to the mRNA).

An "origin of replication" refers to those DNA sequences that participate in DNA synthesis.

A DNA "coding sequence" is a double-stranded DNA sequence which is transcribed and translated into a polypeptide in vivo when placed under the control of appropriate regulatory sequences. The boundaries of the coding sequence are determined by a start codon at the 5 ' (amino) terminus and a translation stop codon at the 3' (carboxyl) terminus. A coding sequence can include, but is not limited to, prokaryotic sequences, cDNA from eukaryotic mRNA, genomic DNA sequences from eukaryotic (e.g., mammalian) DNA, and even synthetic DNA sequences. A polyadenylation signal and transcription termination sequence will usually be located 3' to the coding sequence.

Transcriptional and translational control sequences are DNA regulatory sequences, such as promoters, enhancers, polyadenylation signals, terminators, and the like, that provide for the expression of a coding sequence in a host cell.

A "promoter sequence" is a DNA regulatory region capable of binding RNA polymerase in a cell and initiating transcription of a downstream (3 ' direction) coding sequence. For purposes of defining the present invention, the promoter sequence is bounded at its 3 ' terminus by the transcription initiation site and extends upstream (5' direction) to include the minimum number of bases or elements necessary to initiate transcription at levels detectable above background. Within the promoter sequence will be found a transcription initiation site (conveniently defined by mapping with nuclease SI), as well as protein binding domains (consensus sequences) responsible for the binding of RNA polymerase. Eukaryotic promoters will often, but not always, contain "TATA" boxes and "CAT" boxes. Prokaryotic promoters contain Shine-Dalgarno sequences in addition to the -10 and -35 consensus sequences.

An "expression control sequence" is a DNA sequence that controls and regulates the transcription and translation of another DNA sequence. A coding sequence is "under the control" of transcriptional and translational control sequences in a cell when RNA polymerase transcribes the coding sequence into mRNA, which is then translated into the protein encoded by the coding sequence. A "signal sequence" can be included before the coding sequence. This sequence encodes a signal peptide, N-terminal to the polypeptide, that communicates to the host cell to direct the polypeptide to the cell surface or secrete the polypeptide into the media, and this signal peptide is clipped off by the host cell before the protein leaves the cell. Signal sequences can be found associated with a variety of proteins native to prokaryotes and eukaryotes.

The term "oligonucleotide, " as used herein in referring to the probe of the present invention, is defined as a molecule comprised of two or more ribonucleotides, preferably more than three. Its exact size will depend upon many factors which, in turn, depend upon the ultimate function and use of the oligonucleotide.

The term "primer" as used herein refers to an oligonucleotide, whether occurring naturally as in a purified restriction digest or produced synthetically, which is capable of acting as a point of initiation of synthesis when placed under conditions in which synthesis of a primer extension product, which is complementary to a nucleic acid strand, is induced, i.e., in the presence of nucleotides and an inducing agent such as a DNA polymerase and at a suitable temperature and pH. The primer may be either single-stranded or double-stranded and must be sufficiently long to prime the synthesis of the desired extension product in the presence of the inducing agent. The exact length of the primer will depend upon many factors, including temperature, source of primer and use of the method. For example, for diagnostic applications, depending on the complexity of the target sequence, the oligonucleotide primer typically contains 15-25 or more nucleotides, although it may contain fewer nucleotides.

The primers herein are selected to be "substantially" complementary to different strands of a particular target DNA sequence. This means that the primers must be sufficiently complementary to hybridize with their respective strands. Therefore, the primer sequence need not reflect the exact sequence of the template. For example, a non-complementary nucleotide fragment may be attached to the 5' end of the primer, with the remainder of the primer sequence being complementary to the strand. Alternatively, non-complementary bases or longer sequences can be interspersed into the primer, provided that the primer sequence has sufficient complementarity with the sequence of the strand to hybridize therewith and thereby form the template for the synthesis of the extension product.

As used herein, the terms "restriction endonucleases" and "restriction enzymes" refer to bacterial enzymes, each of which cut double-stranded DNA at or near a specific nucleotide sequence.

A cell has been "transformed" by exogenous or heterologous DNA when such DNA has been introduced inside the cell. The transforming DNA may or may not be integrated (covalently linked) into chromosomal DNA making up the genome of the cell. In prokaryotes, yeast, and mammalian cells for example, the transforming DNA may be maintained on an episomal element such as a plasmid. With respect to eukaryotic cells, a stably transformed cell is one in which the transforming DNA has become integrated into a chromosome so that it is inherited by daughter cells through chromosome replication. This stability is demonstrated by the ability of the eukaryotic cell to establish cell lines or clones comprised of a population of daughter cells containing the transforming DNA. A "clone" is a population of cells derived from a single cell or common ancestor by mitosis. A "cell line" is a clone of a primary cell that is capable of stable growth in vitro for many generations.

Two DNA sequences are "substantially homologous" when at least about 75 % (preferably at least about 80%, and most preferably at least about 90 or 95 %) of the nucleotides match over the defined length of the DNA sequences. Sequences that are substantially homologous can be identified by comparing the sequences using standard software available in sequence data banks, or in a Southern hybridization experiment under, for example, stringent conditions as defined for that particular system. Defining appropriate hybridization conditions is within the skill of the art. See, e.g. , Maniatis et al., supra; DNA Cloning, Vols. I & II, supra; Nucleic Acid Hybridization, supra.

It should be appreciated that also within the scope of the present invention are DNA sequences encoding cig and erg gene products which code for proteins having the same amino acid sequence as SEQ ID NOS:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 27, 29, 31, 33, 35, and 37, but which are degenerate to SEQ ID NOS: l, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21-26, 28, 30, 32, 34, 36, 38, and 39. By "degenerate to" is meant that a different three-letter codon is used to specify a particular amino acid. It is well known in the art that the following codons can be used interchangeably to code for each specific amino acid:

Phenylalanine (Phe or F) UUU or UUC Leucine (Leu or L) UUA or UUG or CUU or CUC or CUA or CUG Isoleucine (He or I) AUU or AUC or AUA Methionine (Met or M) AUG Valine (Val or V) GUU or GUC of GUA or GUG Serine (Ser or S) UCU or UCC or UCA or UCG or AGU or AGC Proline (Pro or P) CCU or CCC or CCA or CCG Threonine (Thr or T) ACU or ACC or ACA or ACG Alanine (Ala or A) GCU or GCG or GCA or GCG Tyros ine (Tyr or Y) UAU or UAC Histidine (His or H) CAU or CAC Glutamine (Gin or Q) CAA or CAG Asparagine (Asn or N) AAU or AAC Lysine (Lys or K) AAA or AAG

Aspartic Acid (Asp or D) GAU or GAC Glutamic Acid (Glu or E) GAA or GAG Cysteine (Cys or C) UGU or UGC Arginine (Arg or R) CGU or CGC or CGA or CGG or AGA or AGG

Glycine (Gly or G) GGU or GGC or GGA or GGG

Tryptophan (Trp or W) UGG

Termination codon UAA (ochre) or UAG (amber) or UGA (opal)

It should be understood that the codons specified above are for RNA sequences. The corresponding codons for DNA have a T substituted for U.

Mutations can be made in SEQ ID NOS: l , 3, 5, 7, 9, 11, 13, 15, 17, 19, 21-26, 28, 30, 32, 34, 36, 38, and 39, such that a particular codon is changed to a codon which codes for a different amino acid. Such a mutation is generally made by making the fewest nucleotide changes possible. A substitution mutation of this sort can be made to change an amino acid in the resulting protein in a non-conservative manner (i.e. , by changing the codon from an amino acid belonging to a grouping of amino acids having a particular size or characteristic to an amino acid belonging to another grouping) or in a conservative manner (i.e.. by changing the codon from an amino acid belonging to a grouping of amino acids having a particular size or characteristic to an amino acid belonging to the same grouping). Such a conservative change generally leads to less change in the structure and function of the resulting protein. A non-conservative change is more likely to alter the structure, activity or function of the resulting protein. The present invention should be considered to include sequences containing conservative changes which do not significantly alter the activity or binding characteristics of the resulting protein.

The following is one example of various groupings of amino acids:

Amino acids with nonpolar R groups

Alanine Valine Leucine Isoleucine Proline Phenylalanine Tryptophan Methionine

Amino acids with uncharged polar R groups

Glycine Serine

Threonine

Cysteine

Tyrosine

Asparagine Glutamine

Amino acids with charged polar R groups (negatively charged at pH 6.0)

Aspartic acid Glutamic acid

Basic amino acids (positively charged at pH 6.0)

Lysine Arginine Histidine (at pH 6.0)

Another grouping may be those amino acids with phenyl groups: Phenylalanine

Tryptophan

Tyrosine

Another grouping may be according to molecular weight (i.e., size of R groups):

Glycine 75

Alanine 89

Serine 105

Proline 115

Valine 117 Threonine 119

Cysteine 121

Leucine 131

Isoleucine 131

Asparagine 132 Aspartic acid 133

Glutamine 146

Lysine 146

Glutamic acid 147

Methionine 149 Histidine (at pH 6.0) 155

Phenylalanine 165

Arginine 174

Tyrosine 181

Tryptophan 204

Particularly preferred substitutions are:

- Lys for Arg and vice versa such that a positive charge may be maintained;

- Glu for Asp and vice versa such that a negative charge may be maintained; - Ser for Thr such that a free -OH can be maintained; and

- Gin for Asn such that a free NH₂ can be maintained.

Amino acid substitutions may also be introduced to substitute an amino acid with a particularly preferable property. For example, a Cys may be introduced a potential site for disulfide bridges with another Cys. A His may be introduced as a particularly "catalytic" site (i.e., His can act as an acid or base and is the most common amino acid in biochemical catalysis). Pro may be introduced because of its particularly planar structure, which induces β-turns in the protein's structure.

Two amino acid sequences are "substantially homologous" when at least about 70% of the amino acid residues (preferably at least about 80% , and most preferably at least about 90 or 95%) are identical, or represent conservative substitutions.

A "heterologous" region of the DNA construct is an identifiable segment of DNA within a larger DNA molecule that is not found in association with the larger molecule in nature. Thus, when the heterologous region encodes a mammalian gene, the gene will usually be flanked by DNA that does not flank the mammalian genomic DNA in the genome of the source organism. Another example of a heterologous coding sequence is a construct where the coding sequence itself is not found in nature (e.g., a cDNA where the genomic coding sequence contains introns, or synthetic sequences having codons different than the native gene). Allelic variations or naturally-occurring mutational events do not give rise to a heterologous region of DNA as defined herein.

An "antibody" is any immunoglobulin, including antibodies and fragments thereof, that binds a specific epitope. The term encompasses polyclonal, monoclonal, and chimeric antibodies, the last mentioned described in further detail in U.S. Patent Nos. 4,816,397 and 4,816,567. An "antibody combining site" is that structural portion of an antibody molecule comprised of heavy and light chain variable and hypervariable regions that specifically binds antigen.

The phrase "antibody molecule" in its various grammatical forms as used herein contemplates both an intact immunoglobulin molecule and an immunologically active portion of an immunoglobulin molecule.

Exemplary antibody molecules are intact immunoglobulin molecules, substantially intact immunoglobulin molecules and those portions of an immunoglobulin molecule that contains the paratope, including those portions known in the art as Fab, Fab' , F(ab')₂ and F(v), which portions are preferred for use in the therapeutic methods described herein.

Fab and F(ab')₂ portions of antibody molecules are prepared by the proteolytic reaction of papain and pepsin, respectively, on substantially intact antibody molecules by methods that are well-known. See for example, U.S. Patent No. 4,342,566 to Theofilopolous et al. Fab' antibody molecule portions are also well- known and are produced from F(ab')₂ portions followed by reduction of the disulfide bonds linking the two heavy chain portions as with mercaptoethanol, and followed by alkylation of the resulting protein mercaptan with a reagent such as iodoacetamide. An antibody containing intact antibody molecules is preferred herein.

The phrase "monoclonal antibody" in its various grammatical forms refers to an antibody having only one species of antibody combining site capable of immunoreacting with a particular antigen. A monoclonal antibody thus typically displays a single binding affinity for any antigen with which it immunoreacts. A monoclonal antibody may therefore contain an antibody molecule having a plurality of antibody combining sites, each immunospecific for a different antigen; e.g., a bispecific (chimeric) monoclonal antibody.

The phrase "pharmaceutically acceptable" refers to molecular entities and compositions that are physiologically tolerable and do not typically produce an allergic or similar untoward reaction, such as gastric upset, dizziness and the like, when administered to a human.

The phrase "therapeutically effective amount" is used herein to mean an amount sufficient to prevent, and preferably reduce by at least about 30 percent, more preferably by at least 50 percent, most preferably by at least 90 percent, a clinically significant change in the S phase activity of a target cellular mass, or other feature of pathology such as for example, elevated blood pressure, fever or white cell count as may attend its presence and activity.

A DNA sequence is "operatively linked" to an expression control sequence when the expression control sequence controls and regulates the transcription and translation of that DNA sequence. The term "operatively linked" includes having an appropriate start signal (e.g., ATG) in front of the DNA sequence to be expressed and maintaining the correct reading frame to permit expression of the DNA sequence under the control of the expression control sequence and production of the desired product encoded by the DNA sequence. If a gene that one desires to insert into a recombinant DNA molecule does not contain an appropriate start signal, such a start signal can be inserted in front of the gene.

The term "standard hybridization conditions" refers to salt and temperature conditions substantially equivalent to 5 x SSC and 65 °C for both hybridization and wash. However, one skilled in the art will appreciate that such "standard hybridization conditions " are dependent on particular conditions including the concentration of sodium and magnesium in the buffer, nucleotide sequence length and concentration, percent mismatch, percent formamide, and the like. Also important in the determination of "standard hybridization conditions" is whether the two sequences hybridizing are RNA-RNA, DNA-DNA or RNA-DNA. Such standard hybridization conditions are easily determined by one skilled in the art according to well known formulae, wherein hybridization is typically 10-20°C below the predicted or determined T_m with washes of higher stringency, if desired.

In its primary aspect, the present invention concerns the identification of cig and erg genes and gene products and their use for the development of diagnostics, drug screening assays, and therapeutics for HCMV and other viral infections.

In a particular embodiment, the present invention relates to all members of the herein disclosed cigs and ergs.

The differential expression of the genes of this invention are diagnostic and characteristic of HCMV infection and interferon treatment. It is envisioned that these genes can be used as markers in assays designed to screen for compounds that are antagonistic to HCMV infection. The assays would utilize sequences that are complementary to the genes that are uniquely either induced or repressed upon HCMV infection as capture probes, attached individually to separate wells in a microtiter plate, or as an array on a flat solid support such as a nylon membrane, nitrocellulose membrane, glass sheet, or plastic sheet, in a hybridization-based assay. Measurement of the levels of expression from the different genes in infected cells, with or without treatment using test compounds, will reflect the efficacy of said compounds at either attenuating the expression of the HCMV-mducible genes {cig), or enhancing the expression of the H MV-repressed genes {erg).

Measurement of expression levels will be facilitated by incorporating a detectable label into all newly synthesized RNAs post-HCMV infection or post-interferon treatment. These detectable labels, for example, radioactive- or fluorescent-labeled ribonucleoside triphosphates, can be added immediately after infection or treatment, and thus be incorporated into any newly synthesized RNA molecule. Alternatively, the capture probe can be labeled with a compound that can be selectively detected upon hybridization to a target. For example a fluorescent label can be detected by fluorescence polarization. In another example, a label (radioactive, fluorescent, chemiluminescent, colorimetric, or enzymatic) can be detected by selective release into solution or retention on the solid support. The former can be accomplished using a nuclease that selectively cleaves the duplex (or heteroduplex in the case of a DNA capture probe and an RNA target), thus releasing the label into the solution phase for subsequent detection. The latter can be accomplished by use of a nuclease that will selectively cleave the single-stranded capture probe but leave the hybridized (duplex or heteroduplex) capture probe, and its attached label, protected and thus retained on the solid support for subsequent detection. In yet another example, antibodies which are specific for heteroduplexes ( . e. DNA capture probe hybridized to RNA target) can be used in a standard ELISA-type assay for detection.

The results from the assays, when used in a drug screening mode, will not only identify compounds that alter HCMV-characteristic expression patterns, but will also reveal what the specific targets are of the various effective compounds identified. The narrowed down list of candidate compounds derived from this first screening will then need to go through a second screening in a model system (either in vitro or in vivo) of HCMV infection to determine true efficacy.

A similar assay system can be used to follow the performance of HCMV-specific drugs in patients. This can be a valuable tool in monitoring the effectiveness of a patient's treatment regimen that ultimately can lead to tailoring the treatment to best fit the patient. Clearly, the system can be simplified be using a single probe that is diagnostic of the efficacy of the particular compound being used for treatment. As stated above, the present invention also relates to a recombinant DNA molecule or cloned gene, or a degenerate variant thereof, which encodes a cig or erg gene product, or a fragment thereof, that possesses an amino acid sequence set forth in the Sequence Listing (SEQ ID NOS:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 27, 29, 31 , 33, 35, and 37); preferably a nucleic acid molecule, in particular a recombinant DNA molecule or cloned gene, encoding the cig or erg gene product has a nucleotide sequence or is complementary to a DNA sequence shown in the Sequence Listing (SEQ ID NOS: l , 3, 5, 7, 9, 11 , 13, 15, 17, 19, 21-26, 28, 30, 32, 34, 36, 38, and 39).

The possibilities both diagnostic and therapeutic that are raised by the existence of the cigs and ergs, derive from the fact that they are either selectively expressed or repressed in response to both HCMV infection and interferon treatment. As suggested earlier and elaborated further on herein, the present invention contemplates pharmaceutical intervention in the cascade of reactions in which the cig and erg gene products are implicated, to modulate the activity initiated by HCMV or other viral infection.

As discussed earlier, the cig and erg gene products or their binding partners or other ligands or agents exhibiting either mimicry or antagonism to the cig and erg gene products or control over their production, may be prepared in pharmaceutical compositions, with a suitable carrier and at a strength effective for administration by various means to a patient experiencing an adverse medical condition associated with HCMV or other viral infection for the treatment thereof. A variety of administrative techniques may be utilized, among them parenteral techniques such as subcutaneous, intravenous and intraperitoneal injections, catheterizations and the like. Average quantities of the cig or erg gene product or their subunits may vary and in particular should be based upon the recommendations and prescription of a qualified physician or veterinarian. Also, antibodies including both polyclonal and monoclonal antibodies, and drugs that modulate the production or activity of the cig or erg gene products and/or their subunits may possess certain diagnostic applications and may for example, be utilized for the purpose of detecting and/or measuring conditions such as viral infection or the like. For example, the cig and erg gene products or their subunits may be used to produce both polyclonal and monoclonal antibodies to themselves in a variety of cellular media, by known techniques such as the hybridoma technique utilizing, for example, fused mouse spleen lymphocytes and myeloma cells. Likewise, small molecules that mimic or antagonize the activity (ies) of the cig or erg gene products of the invention may be discovered or synthesized, and may be used in diagnostic and/or therapeutic protocols.

The general methodology for making monoclonal antibodies by hybridomas is well known. Immortal, antibody-producing cell lines can also be created by techniques other than fusion, such as direct transformation of B lymphocytes with oncogenic DNA, or transfection with Epstein-Barr virus. See, e.g. , M. Schreier et al. ,

"Hybridoma Techniques" (1980); Hammerling et al. , "Monoclonal Antibodies And T-cell Hybridomas" (1981); Kennett et al. , "Monoclonal Antibodies" (1980); see also U.S. Patent Nos. 4,341 ,761; 4,399, 121 ; 4,427,783; 4,444,887; 4,451,570; 4,466,917; 4,472,500; 4,491,632; 4,493,890.

Panels of monoclonal antibodies produced against cig or erg gene product peptides can be screened for various properties; i.e. , isotype, epitope, affinity, etc. Of particular interest are monoclonal antibodies that neutralize the activity of the cig gene products or their subunits. Such monoclonals can be readily identified in cig gene product activity assays. High affinity antibodies are also useful when immunoaffinity purification of native or recombinant cig or erg gene product is possible. Preferably, the anti-c/g or erg gene product antibody used in the diagnostic methods of this invention is an affinity purified polyclonal antibody. More preferably, the antibody is a monoclonal antibody (mAb). In addition, it is preferable for the anti- cig or erg gene product antibody molecules used herein be in the form of Fab, Fab' , F(ab')₂ or F(v) portions of whole antibody molecules.

As suggested earlier, the diagnostic method of the present invention comprises examining a cellular sample or medium by means of an assay including an effective amount of an antagonist to a cig or erg gene product/protein, such as an anti-c/g or erg gene product antibody, preferably an affinity -purified polyclonal antibody, and more preferably a mAb. In addition, it is preferable for the anti-c/g or erg gene product antibody molecules used herein be in the form of Fab, Fab' , F(ab'^ or F(v) portions or whole antibody molecules. As previously discussed, patients capable of benefiting from this method include those suffering from viral infection (particularly with HCMV) or other like pathological derangement. Methods for isolating the cig or erg gene products and inducing anti-c/g or erg gene product antibodies and for determining and optimizing the ability of anti-c/g or erg gene product antibodies to assist in the examination of the target cells are all well-known in the art.

Methods for producing polyclonal anti-polypeptide antibodies are well-known in the art. See U.S. Patent No. 4,493,795 to Nestor et al. A monoclonal antibody, typically containing Fab and/or F(ab')₂ portions of useful antibody molecules, can be prepared using the hybridoma technology described in Antibodies - A Laboratory Manual, Harlow and Lane, eds., Cold Spring Harbor Laboratory, New York (1988), which is incorporated herein by reference. Briefly, to form the hybridoma from which the monoclonal antibody composition is produced, a myeloma or other self-perpetuating cell line is fused with lymphocytes obtained from the spleen of a mammal hyperimmunized with a cig or erg gene product-binding portion thereof, or cig or erg gene product, or an origin-specific DNA-binding portion thereof. Splenocytes are typically fused with myeloma cells using polyethylene glycol (PEG) 6000. Fused hybrids are selected by their sensitivity to HAT. Hybridomas producing a monoclonal antibody useful in practicing this invention are identified by their ability to immunoreact with the present cig or erg gene product and their ability to inhibit specified cig or erg gene product activity in target cells.

A monoclonal antibody useful in practicing the present invention can be produced by initiating a monoclonal hybridoma culture comprising a nutrient medium containing a hybridoma that secretes antibody molecules of the appropriate antigen specificity. The culture is maintained under conditions and for a time period sufficient for the hybridoma to secrete the antibody molecules into the medium. The antibody-containing medium is then collected. The antibody molecules can then be further isolated by well-known techniques.

Media useful for the preparation of these compositions are both well-known in the art and commercially available and include synthetic culture media, inbred mice and the like. An exemplary synthetic medium is Dulbecco's minimal essential medium (DMEM; Dulbecco et al. , Virol. 8:396 (1959)) supplemented with 4.5 gm/1 glucose, 20 mm glutamine, and 20% fetal calf serum. An exemplary inbred mouse strain is the Balb/c.

Methods for producing monoclonal anti-c/g or erg gene product antibodies are also well-known in the art. See Niman et al., Proc. Natl. Acad. Sci. USA, 80:4949-4953 (1983). Typically, the present cig or erg gene product or a peptide analog is used either alone or conjugated to an immunogenic carrier, as the immunogen in the before described procedure for producing anti-c/g or erg gene product monoclonal antibodies. The hybridomas are screened for the ability to produce an antibody that immunoreacts with the cig or erg gene product peptide analog and the present cig or erg gene product. The present invention further contemplates therapeutic compositions useful in practicing the therapeutic methods of this invention. A subject therapeutic composition includes, in admixture, a pharmaceutically acceptable excipient (carrier) and one or more of a cig or erg gene product, polypeptide analog thereof or fragment thereof, as described herein as an active ingredient. In a preferred embodiment, the composition comprises an antigen capable of modulating the specific binding of the present cig or erg gene product within a target cell.

The preparation of therapeutic compositions which contain polypeptides, analogs or active fragments as active ingredients is well understood in the art. Typically, such compositions are prepared as injectables, either as liquid solutions or suspensions, however, solid forms suitable for solution in, or suspension in, liquid prior to injection can also be prepared. The preparation can also be emulsified. The active therapeutic ingredient is often mixed with excipients which are pharmaceutically acceptable and compatible with the active ingredient. Suitable excipients are, for example, water, saline, dextrose, glycerol, ethanol, or the like and combinations thereof. In addition, if desired, the composition can contain minor amounts of auxiliary substances such as wetting or emulsifying agents, pH buffering agents which enhance the effectiveness of the active ingredient.

A polypeptide, analog or active fragment can be formulated into the therapeutic composition as neutralized pharmaceutically acceptable salt forms.

Pharmaceutically acceptable salts include the acid addition salts (formed with the free amino groups of the polypeptide or antibody molecule) and which are formed with inorganic acids such as, for example, hydrochloric or phosphoric acids, or such organic acids as acetic, oxalic, tartaric, mandelic, and the like. Salts formed from the free carboxyl groups can also be derived from inorganic bases such as, for example, sodium, potassium, ammonium, calcium, or ferric hydroxides, and such organic bases as isopropylamine, trimethylamine, 2-ethylamino ethanol, histidine, procaine, and the like. The therapeutic polypeptide-, analog- or active fragment-containing compositions are conventionally administered intravenously, as by injection of a unit dose, for example. The term "unit dose" when used in reference to a therapeutic composition of the present invention refers to physically discrete units suitable as unitary dosage for humans, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect in association with the required diluent; i.e. , carrier, or vehicle.

The compositions are administered in a manner compatible with the dosage formulation, and in a therapeutically effective amount. The quantity to be administered depends on the subject to be treated, capacity of the subject's immune system to utilize the active ingredient, and degree of inhibition or neutralization of ^~ binding capacity desired. Precise amounts of active ingredient required to be administered depend on the judgment of the practitioner and are peculiar to each individual. However, suitable dosages may range from about 0.1 to 20, preferably about 0.5 to about 10, and more preferably one to several, milligrams of active ingredient per kilogram body weight of individual per day and depend on the route of administration. Suitable regimes for initial administration and booster shots are also variable, but are typified by an initial administration followed by repeated doses at one or more hour intervals by a subsequent injection or other administration. Alternatively, continuous intravenous infusion sufficient to maintain concentrations of ten nanomolar to ten micromolar in the blood are contemplated.

The therapeutic compositions may further include an effective amount of the cig or erg gene product antagonist or analog thereof, and one or more of the following active ingredients: an antibiotic, a steroid. Exemplary formulations are given below:

Formulations Intravenous Formulation I

Ingredient mg/ml cefotaxime 250.0 cig or erg gene product 10.0 dextrose USP 45.0 sodium bisulfite USP 3.2 edetate disodium USP 0.1 water for injection q.s. a. d. 1.0 ml

Intravenous Formulation II Ingredient mg/ml ampicillin 250.0 cig or erg gene product 10.0 sodium bisulfite USP 3.2 disodium edetate USP 0.1 water for injection q.s. a. d. 1.0 ml

Intravenous Formulation III

Ingredient mg/ml gentamicin (charged as sulfate) 40.0 cig or erg gene product 10.0 sodium bisulfite USP 3.2 disodium edetate USP 0.1 water for injection q.s.a.d. 1.0 ml

Intravenous Formulation IV

Ingredient mg/ml cig or erg gene product 10.0 dextrose USP 45.0 sodium bisulfite USP 3.2 edetate disodium USP 0.1 water for injection q.s.a.d. 1.0 ml

Intravenous Formulation V

Ingredient mg/ml cig or erg gene product antagonist 5.0 sodium bisulfite USP 3.2 disodium edetate USP 0.1 water for injection q.s.a.d. 1.0 ml

As used herein, "pg" means picogram, "ng" means nanogram, "ug" or "μg" mean microgram, "mg" means milligram, "ul" or "μl" mean microliter, "ml" means milliliter, "1" means liter.

Another feature of this invention is the expression of the DNA sequences disclosed herein. As is well known in the art, DNA sequences may be expressed by operatively linking them to an expression control sequence in an appropriate expression vector and employing that expression vector to transform an appropriate unicellular host.

Such operative linking of a DNA sequence of this invention to an expression control sequence, of course, includes, if not already part of the DNA sequence, the provision of an initiation codon, ATG, in the correct reading frame upstream of the DNA sequence.

A wide variety of host/expression vector combinations may be employed in expressing the DNA sequences of this invention. Useful expression vectors, for example, may consist of segments of chromosomal, non-chromosomal and synthetic DNA sequences. Suitable vectors include derivatives of SV40 and known bacterial plasmids, e.g., E. coli plasmids col Εl, pCRl, pBR322, pMB9 and their derivatives, plasmids such as RP4; phage DNAS, e.g. , the numerous derivatives of phage λ, e.g. , NM989, and other phage DNA, e.g. , M13 and filamentous single stranded phage DNA; yeast plasmids such as the 2μ plasmid or derivatives thereof; vectors useful in eukaryotic cells, such as vectors useful in insect or mammalian cells; vectors derived from combinations of plasmids and phage DNAs, such as plasmids that have been modified to employ phage DNA or other expression control sequences; and the like.

Any of a wide variety of expression control sequences — sequences that control the expression of a DNA sequence operatively linked to it - may be used in these vectors to express the DNA sequences of this invention. Such useful expression control sequences include, for example, the early or late promoters of SV40, CMV, vaccinia, polyoma or adenovirus, the lac system, the trp system, the TAC system, the TRC system, the LTR system, the major operator and promoter regions of phage λ, the control regions of fd coat protein, the promoter for 3 -phosphogly cerate kinase or other glycolytic enzymes, the promoters of acid phosphatase (e.g., Pho5), the promoters of the yeast α-mating factors, and other sequences known to control the expression of genes of prokaryotic or eukaryotic cells or their viruses, and various combinations thereof.

A wide variety of unicellular host cells are also useful in expressing the DNA sequences of this invention. These hosts may include well known eukaryotic and prokaryotic hosts, such as strains of E. coli, Pseudomonas, Bacillus, Streptomyces, fungi such as yeasts, and animal cells, such as CHO, Rl.l, B-W and L-M cells, African Green Monkey kidney cells (e.g., COS 1, COS 7, BSC1, BSC40, and BMT10), insect cells (e.g., Sf9), and human cells and plant cells in tissue culture.

It will be understood that not all vectors, expression control sequences and hosts will function equally well to express the DNA sequences of this invention. Neither will all hosts function equally well with the same expression system. However, one skilled in the art will be able to select the proper vectors, expression control sequences, and hosts without undue experimentation to accomplish the desired expression without departing from the scope of this invention. For example, in selecting a vector, the host must be considered because the vector must function in it. The vector's copy number, the ability to control that copy number, and the expression of any other proteins encoded by the vector, such as antibiotic markers, will also be considered.

In selecting an expression control sequence, a variety of factors will normally be considered. These include, for example, the relative strength of the system, its controllability, and its compatibility with the particular DNA sequence or gene to be expressed, particularly as regards potential secondary structures. Suitable unicellular hosts will be selected by consideration of, e.g. , their compatibility with the chosen vector, their secretion characteristics, their ability to fold proteins correctly, and their fermentation requirements, as well as the toxicity to the host of the product encoded by the DNA sequences to be expressed, and the ease of purification of the expression products.

Considering these and other factors a person skilled in the art will be able to construct a variety of vector/expression control sequence/host combinations that will express the DNA sequences of this invention on fermentation or in large scale animal culture.

It is further intended that cig or erg gene product analogs may be prepared from nucleotide sequences of the protein complex/subunit derived within the scope of the present invention. Analogs, such as fragments, may be produced, for example, by pepsin digestion of cig or erg gene product material. Other analogs, such as muteins, can be produced by standard site-directed mutagenesis of cig or erg gene product coding sequences. Analogs exhibiting "cig or erg gene product activity" such as small molecules, whether functioning as promoters or inhibitors, may be identified by known in vivo and/or in vitro assays.

As mentioned above, a DNA sequence encoding cig or erg gene product can be prepared synthetically rather than cloned. The DNA sequence can be designed with the appropriate codons for the cig or erg gene product amino acid sequence. In general, one will select preferred codons for the intended host if the sequence will be used for expression. The complete sequence is assembled from overlapping oligonucleotides prepared by standard methods and assembled into a complete coding sequence. See, e.g., Edge, Nature, 292:756 (1981); Nambair et al. , Science, 223:1299 (1984); Jay et al., J. Biol. Chem. , 259:6311 (1984).

Synthetic DNA sequences allow convenient construction of genes which will express cig or erg gene product analogs or "muteins" . Alternatively, DNA encoding muteins can be made by site-directed mutagenesis of native cig or erg gene product genes or cDNAs, and muteins can be made directly using conventional polypeptide synthesis.

A general method for site-specific incorporation of unnatural amino acids into proteins is described in Christopher J. Noren, Spencer J. Anthony-Cahill, Michael C. Griffith, Peter G. Schultz, Science, 244: 182-188 (April 1989). This method may be used to create analogs with unnatural amino acids.

The present invention extends to the preparation of antisense oligonucleotides and ribozymes that may be used to interfere with the expression of the ^~ at the translational level. This approach utilizes antisense nucleic acid and ribozymes to block translation of a specific mRNA, either by masking that mRNA with an antisense nucleic acid or cleaving it with a ribozyme. Antisense nucleic acids are DNA or RNA molecules that are complementary to at least a portion of a specific mRNA molecule. (See Weintraub, 1990; Marcus-Sekura, 1988.) In the cell, they hybridize to that mRNA, forming a double stranded molecule. The cell does not translate an mRNA in this double-stranded form. Therefore, antisense nucleic acids interfere with the expression of mRNA into protein. Oligomers of about fifteen nucleotides and molecules that hybridize to the AUG initiation codon will be particularly efficient, since they are easy to synthesize and are likely to pose fewer problems than larger molecules when introducing them into ^"-producing cells. Antisense methods have been used to inhibit the expression of many genes in vitro (Marcus-Sekura, 1988; Hambor et al. , 1988).

Ribozymes are RNA molecules possessing the ability to specifically cleave other single stranded RNA molecules in a manner somewhat analogous to DNA restriction endonucleases. Ribozymes were discovered from the observation that certain mRNAs have the ability to excise their own introns. By modifying the nucleotide sequence of these RNAs, researchers have been able to engineer molecules that recognize specific nucleotide sequences in an RNA molecule and cleave it (Cech, 1988.). Because they are sequence-specific, only mRNAs with particular sequences are inactivated.

Investigators have identified two types of ribozymes, Tetrahymena-type and

"hammerhead "-type. (Hasselhoff and Gerlach, 1988) Tetrahymena-type ribozymes recognize four-base sequences, while "hammerhead "-type recognize eleven- to eighteen-base sequences. The longer the recognition sequence, the more likely it is to occur exclusively in the target mRNA species. Therefore, hammerhead-type ribozymes are preferable to Tetrahymena-type ribozymes for inactivating a specific mRNA species, and eighteen base recognition sequences are preferable to shorter recognition sequences. The DNA sequences described herein may thus be used to prepare antisense molecules against, and ribozymes that cleave mRNAs for cig or erg gene product and their ligands.

In one embodiment, a gene encoding a cig or erg gene product or polypeptide domain fragment thereof is introduced in vivo in a viral vector. Such vectors include an attenuated or defective DNA virus, such as but not limited to herpes simplex virus (HSV), papillomavirus, Epstein Barr virus (EBV), adenovirus, adeno- associated virus (AAV), and the like. Defective viruses, which entirely or almost entirely lack viral genes, are preferred. Defective virus is not infective after introduction into a cell. Use of defective viral vectors allows for administration to cells in a specific, localized area, without concern that the vector can infect other cells. Examples of particular vectors include, but are not limited to, a defective herpes virus-1 (HSV-1) vector [Kaplitt et al. , Molec. Cell. Neurosci. 2:320-330 (1991)], an attenuated adenovirus vector, such as the vector described by Stratford - Perricaudet et al. [J. Clin. Invest. 90:626-630 (1992)], and a defective adeno- associated virus vector [Samulski et al. , J. Virol. 61:3096-3101 (1987); Samulski et al. , J. Virol. 63:3822-3828 (1989)].

Preferably, for in vitro administration, an appropriate immunosuppressive treatment is employed in conjunction with the viral vector, e.g. , adenovirus vector, to avoid immuno-deactivation of the viral vector and transfected cells. For example, immunosuppressive cytokines, such as interleukin-12 (IL-12), interferon-γ (IFN-γ), or anti-CD4 antibody, can be administered to block humoral or cellular immune responses to the viral vectors [see, e.g. , Wilson, Nature Medicine (1995)] . In addition, it is advantageous to employ a viral vector that is engineered to express a minimal number of antigens.

In another embodiment the gene can be introduced in a retroviral vector, e.g. , as described in Anderson et al., U.S. Patent No. 5,399,346; Mann et al., 1983, Cell 33: 153; Temin et al., U.S. Patent No. 4,650,764; Temin et al., U.S. Patent No. 4,980,289; Markowitz et al., 1988, J. Virol. 62:1120; Temin et al., U.S. Patent No. 5,124,263; International Patent Publication No. WO 95/07358, published March 16, 1995, by Dougherty et al.; and Kuo et al., 1993, Blood 82:845.

Targeted gene delivery is described in International Patent Publication WO 95/28494, published October 1995.

Alternatively, the vector can be introduced in vivo by lipofection. For the past decade, there has been increasing use of liposomes for encapsulation and transfection of nucleic acids in vitro. Synthetic cationic lipids designed to limit the difficulties and dangers encountered with liposome mediated transfection can be used to prepare liposomes for in vivo transfection of a gene encoding a marker [Feigner, et. al., Proc. Natl. Acad. Sci. U.S.A. 84:7413-7417 (1987); see Mackey, et al. , Proc. Natl. Acad. Sci. U.S.A. 85:8027-8031 (1988)] . The use of cationic lipids may promote encapsulation of negatively charged nucleic acids, and also promote fusion with negatively charged cell membranes [Feigner and Ringold,

Science 337:387-388 (1989)] . The use of lipofection to introduce exogenous genes into the specific organs in vivo has certain practical advantages. Molecular targeting of liposomes to specific cells represents one area of benefit. It is clear that directing transfection to particular cell types would be particularly advantageous in a tissue with cellular heterogeneity, such as pancreas, liver, kidney, and the brain. Lipids may be chemically coupled to other molecules for the purpose of targeting [see Mackey, et. al., supra]. Targeted peptides, e.g. , hormones or neurotransmitters, and proteins such as antibodies, or non-peptide molecules could be coupled to liposomes chemically.

It is also possible to introduce the vector in vivo as a naked DNA plasmid. Naked DNA vectors for gene therapy can be introduced into the desired host cells by methods known in the art, e.g. , transfection, electroporation, microinjection, transduction, cell fusion, DEAE dextran, calcium phosphate precipitation, use of a gene gun, or use of a DNA vector transporter [see, e.g. , Wu et al., J. Biol. Chem. 267:963-967 (1992); Wu and Wu, I. Biol. Chem. 263: 14621-14624 (1988); Hartmut et al. , Canadian Patent Application No. 2,012,311, filed March 15, 1990].

In a preferred embodiment of the present invention, a gene therapy vector as described above employs a transcription control sequence operably associated with the cig or erg sequence inserted in the vector. That is, a specific expression vector of the present invention can be used in gene therapy.

Such an expression vector is particularly useful to regulate expression of a therapeutic cig or erg. In one embodiment, the present invention contemplates constitutive expression of the cig or erg, even if at low levels. Various therapeutic heterologous genes can be inserted in a gene therapy vector of the invention such as but not limited to adenosine deaminase (ADA) to treat severe combined immunodeficiency (SCID); marker genes or lymphokine genes into tumor infiltrating (TIL) T cells [Kasis et al. , Proc. Natl. Acad. Sci. U.S.A. 87:473 (1990); Culver et al. , ibid. 88:3155 (1991)]; genes for clotting factors such as Factor VIII and Factor IX for treating hemophilia [Dwarki et al. Proc. Natl. Acad. Sci. USA, 92: 1023-1027 (19950); Thompson, Thromb. and Haemostatis , 66: 119- 122 (1991)]; and various other well known therapeutic genes such as, but not limited to, β-globin, dystrophin, insulin, erythropoietin, growth hormone, glucocerebrosidase, β-glucuronidase, -antitrypsin, phenylalanine hydroxylase, tyrosine hydroxylase, ornithine transcarbamylase, apolipoproteins, and the like. In general, see U.S. Patent No. 5,399,346 to Anderson et al.

In another aspect, the present invention provides for regulated expression of the heterologous gene in concert with expression of proteins under control of *** upon commitment to DNA synthesis. Concerted control of such heterologous genes may be particularly useful in the context of treatment for proliferative disorders, such as tumors and cancers, when the heterologous gene encodes a targeting marker or immunomodulatory cytokine that enhances targeting of the tumor cell by host immune system mechanisms. Examples of such heterologous genes for immunomodulatory (or immuno-effector) molecules include, but are not limited to, interferon-α, interferon-γ, interferon-β, interferon-ω, interferon-τ, tumor necrosis factor-α, tumor necrosis factor-β, interleukin-2, interleukin-7, inter leukin- 12, inter leukin- 15, B7-1 T cell co-stimulatory molecule, B7-2 T cell co-stimulatory molecule, immune cell adhesion molecule (ICAM) -I T cell co-stimulatory molecule, granulocyte colony stimulatory factor, granulocyte-macrophage colony stimulatory factor, and combinations thereof.

In a further embodiment, the present invention provides for co-expression of cig or erg and a therapeutic heterologous gene under control of a specific DNA recognition sequence by providing a gene therapy expression vector comprising both a cig or erg coding gene and a gene under control of, inter alia, the cig or erg regulatory sequence. In one embodiment, these elements are provided on separate vectors, e.g. , as exemplified infra. These elements may be provided in a single expression vector.

The present invention also relates to a variety of diagnostic applications, including methods for detecting the presence of stimuli such as the earlier referenced polypeptide ligands, by reference to their ability to elicit the activities which are mediated by the present cig or erg gene products. As mentioned earlier, the cig or erg gene products can be used to produce antibodies to itself by a variety of known techniques, and such antibodies could then be isolated and utilized as in tests for the presence of particular cig or erg gene product activity in suspect target cells.

As described in detail above, antibody (ies) to the cig or erg gene products can be produced and isolated by standard methods including the well known hybridoma techniques. For convenience, the antibody(ies) to the cig or erg gene products will be referred to herein as A and antibody (ies) raised in another species as Ab_j.

The presence of ^~ in cells can be ascertained by the usual immunological procedures applicable to such determinations. A number of useful procedures are known. Three such procedures which are especially useful utilize either the cig or erg gene product labeled with a detectable label, antibody Afy labeled with a detectable label, or antibody Ab₂ labeled with a detectable label. The procedures may be summarized by the following equations wherein the asterisk indicates that the particle is labeled, and "^~ " stands for the cig or erg gene product: A. ^~* + Ab] = ^~*Ab,

B. ^~ + Ab* = ^"Ab^

C. ^" + Ab, + Ab₂* = ^~Ab,Ab₂*

The procedures and their application are all familiar to those skilled in the art and accordingly may be utilized within the scope of the present invention. The "competitive" procedure, Procedure A, is described in U.S. Patent Nos. 3,654,090 and 3,850,752. Procedure C, the "sandwich" procedure, is described in U.S. Patent Nos. RE 31,006 and 4,016,043. Still other procedures are known such as the "double antibody," or "DASP" procedure.

In each instance, the cig or erg gene product forms complexes with one or more antibody(ies) or binding partners and one member of the complex is labeled with a detectable label. The fact that a complex has formed and, if desired, the amount thereof, can be determined by known methods applicable to the detection of labels.

It will be seen from the above, that a characteristic property of At^ is that it will react with Ab_! . This is because A raised in one mammalian species has been used in another species as an antigen to raise the antibody Ab,. For example, Ab₂ may be raised in goats using rabbit antibodies as antigens. At^ therefore would be anti-rabbit antibody raised in goats. For purposes of this description and claims, Ab, will be referred to as a primary or anti-c/g or erg gene product antibody, and Ab₂ will be referred to as a secondary or anti-Ab_j antibody.

The labels most commonly employed for these studies are radioactive elements, enzymes, chemicals which fluoresce when exposed to ultraviolet light, and others.

A number of fluorescent materials are known and can be utilized as labels. These include, for example, fluorescein, rhodamine, auramine, Texas Red, AMCA blue and Lucifer Yellow. A particular detecting material is anti-rabbit antibody prepared in goats and conjugated with fluorescein through an isothiocyanate.

The cig or erg gene product or its binding partner (s) can also be labeled with a radioactive element or with an enzyme. The radioactive label can be detected by any of the currently available counting procedures. The preferred isotope may be selected from ³H, ¹⁴C, ³²P, ³ P,- ³⁵S, ³⁶C1, ⁵¹Cr, ⁵⁷Co, ⁵⁸Co, ⁵⁹Fe, ^Y, ¹²⁵I, ¹³¹I, and ¹⁸⁶Re.

Enzyme labels are likewise useful, and can be detected by any of the presently utilized colorimetric, spectrophotometric, fluorospectrophotometric, amperometric or gasometric techniques. The enzyme is conjugated to the selected particle by reaction with bridging molecules such as carbodiimides, diisocyanates, glutaraldehyde and the like. Many enzymes which can be used in these procedures are known and can be utilized. The preferred are peroxidase, β-glucuronidase, β-D-glucosidase, β-D-galactosidase, urease, glucose oxidase plus peroxidase and alkaline phosphatase. U.S. Patent Nos. 3,654,090; 3,850,752; and 4,016,043 are referred to by way of example for their disclosure of alternate labeling material and methods. A particular assay system developed and utilized in accordance with the present invention, is known as a receptor assay. In a receptor assay, the material to be assayed is appropriately labeled and then certain cellular test colonies are inoculated with a quantity of both the labeled and unlabeled material after which binding studies are conducted to determine the extent to which the labeled material binds to the cell receptors. In this way, differences in affinity between materials can be ascertained.

Accordingly, a purified quantity of the cig or erg gene product may be radiolabeled and combined, for example, with antibodies or other inhibitors thereto, after which binding studies would be carried out. Solutions would then be prepared that contain various quantities of labeled and unlabeled uncombined cig or erg gene product, and cell samples would then be inoculated and thereafter incubated. The resulting cell monolayers are then washed, solubilized and then counted in a gamma counter for a length of time sufficient to yield a standard error of < 5 % . These data are then subjected to Scatchard analysis after which observations and conclusions regarding material activity can be drawn. While the foregoing is exemplary, it illustrates the manner in which a receptor assay may be performed and utilized, in the instance where the cellular binding ability of the assayed material may serve as a distinguishing characteristic.

An assay useful and contemplated in accordance with the present invention is known as a "cis/trans" assay. Briefly, this assay employs two genetic constructs, one of which is typically a plasmid that continually expresses a particular receptor of interest when transfected into an appropriate cell line, and the second of which is a plasmid that expresses a reporter such as luciferase, under the control of a receptor/ligand complex. Thus, for example, if it is desired to evaluate a compound as a ligand for a particular receptor, one of the plasmids would be a construct that results in expression of the receptor in the chosen cell line, while the second plasmid would possess a promoter linked to the luciferase gene in which the response element to the particular receptor is inserted. If the compound under test is an agonist for the receptor, the ligand will complex with the receptor, and the resulting complex will bind the response element and initiate transcription of the luciferase gene. The resulting chemiluminescence is then measured photometrically, and dose response curves are obtained and compared to those of known ligands. The foregoing protocol is described in detail in U.S. Patent No. 4,981,784 and PCT International Publication No. WO 88/03168, for which purpose the artisan is referred.

In a further embodiment of this invention, commercial test kits suitable for use by a medical specialist may be prepared to determine the presence or absence of predetermined cig or erg gene product activity in suspected target cells. In accordance with the testing techniques discussed above, one class of such kits will contain at least the labeled cig or erg gene product or its binding partner, for instance an antibody specific thereto, and directions, of course, depending upon the method selected, e.g. , "competitive," "sandwich, " "DASP" and the like. The kits may also contain peripheral reagents such as buffers, stabilizers, etc.

Accordingly, a test kit may be prepared for the demonstration of the presence or capability of cells for predetermined cig or erg gene product activity, comprising:

(a) a predetermined amount of at least one labeled immunochemically reactive component obtained by the direct or indirect attachment of the present cig or erg gene product factor or a specific binding partner thereto, to a detectable label;

(b) other reagents; and

(c) directions for use of said kit.

More specifically, the diagnostic test kit may comprise: (a) a known amount of the cig or erg gene products as described above (or a binding partner) generally bound to a solid phase to form an immunosorbent, or in the alternative, bound to a suitable tag, or plural such end products, etc. (or their binding partners) one of each;

(b) if necessary, other reagents; and

(c) directions for use of said test kit.

In a further variation, the test kit may be prepared and used for the purposes stated above, which operates according to a predetermined protocol (e.g. "competitive, " "sandwich, " "double antibody," etc.), and comprises:

(a) a labeled component which has been obtained by coupling the ^~ to a detectable label; (b) one or more additional immunochemical reagents of which at least one reagent is a ligand or an immobilized ligand, which ligand is selected from the group consisting of:

(i) a ligand capable of binding with the labeled component (a); (ii) a ligand capable of binding with a binding partner of the labeled component (a);

(iii) a ligand capable of binding with at least one of the component(s) to be determined; and

(iv) a ligand capable of binding with at least one of the binding partners of at least one of the component(s) to be determined; and (c) directions for the performance of a protocol for the detection and/or determination of one or more components of an immunochemical reaction between the ^~ and a specific binding partner thereto.

In accordance with the above, an assay system for screening potential drugs effective to modulate the activity of the cig or erg gene product may be prepared. The cig or erg gene product may be introduced into a test system, and the prospective drug may also be introduced into the resulting cell culture, and the culture thereafter examined to observe any changes in the cig or erg gene products activity of the cells, due either to the addition of the prospective drug alone, or due to the effect of added quantities of the known cig or erg gene product.

The following examples are presented in order to more fully illustrate the preferred embodiments of the invention. They should in no way be construed, however, as limiting the broad scope of the invention.

EXAMPLE 1 Cells and viruses. Primary human foreskin (HF) cells were cultures in medium containing 10% fetal calf serum. Cells were held at confluence for 3-4 days prior to experimentation. To avoid cell stimulation by fresh serum, treated cells were returned to the medium in which they were previously maintained. Where indicated, HF cells were treated with 500U/ml interferon-α and β (Sigman) for 4 h, and 100 μg/ml cyclohexamide was used to block protein synthesis.

HF cells were infected with HCMV strain AD 169 (18), Towne (19) or Toledo (20). Wild-type adenovirus, _./309 (21), and herpes simplex virus type 1 (HSV-1) were also used. Infections with HCMV or HSV-1 were performed at a multiplicity of 3 plaque-forming units/cell, and adenovirus was used at a multiplicity of 30 plaque-forming units/cell. For inactivation with UV light, 5 ml medium containing HCMV was placed in a 15 -cm-diameter dish, and irradiated at 2J/m2/sec for 10 min with mixing every 2 min. UV-treated stocks failed to produce detectable IE1 and IE2 protein at 8 or 36 h after infection. For neutralization, 50 μl HCMV stock was incubated with 20 μl neutralizing antibody (gift from Jay Nelson, University of Oregon) for 1 h at room temperature. Neutralization was confirmed by plaque assay. HCMV particles were concentrated and purified as described previously (22). HCMV membrane and tegument/capsid proteins were separated and isolated by detergent stripping (23).

EXAMPLE 2 Differential display assay. For differential display analysis (16-17), HF cells were mock- infected or infected with AD 169 or UV-inactivated AD 169. Total RNA was isolated 8 h later by using the TRIZOL Reagent (Life Technologies). First-strand cDNAs were synthesized using oligo(dT), and amplified in parallel PCR reactions in the presence of [α-³³P]dCTP using 135 combinations of 19 primers (Delta RNA Fingerprinting Kit, Clontech). The products were separated by electrophoresis on 5 % polyacrylamide gels containing 8M urea. Differentially expressed bands were cut out of the gel, reamplified using the appropriate primer set, cloned into the pT7Blue T- Vector (Novagen), sequenced, and the results were analyzed by BLAST search (National Center for Biotechnology Information).

EXAMPLE 3 Assays for RNAs and proteins. For Northern blot assays 5 μg RNA from mock- or HCMV-infected HF cells was probed with random hexanucleotide-primed ³²P- labeled cDNA clones. The probes for mxA, isgl5K and interferon-β were the partial cDNA sequences purified from I.M.A.G.E. Consortium (LLNL) clones (Genome Systems). For Western blot assays, three mouse monoclonal antibodies that recognize HCMV proteins, anti-IEl/IE2 (MAb810, Chemicon), anti-pp65 (2) and anti-glycoprotein B (Goodwin Institute), were used as the primary antibodies. Mab810 and anti-pp65 were also used for immunofluorescent staining.

EXAMPLE 4

Analysis of Cytomegalovirus-Induced RNAs. HCMV could alter host cell gene expression through the action of virion proteins or by the synthesis of new viral proteins after infection. To distinguish between these possibilities, we compared competent virus (HCMV) to UV-inactivated virus (UV HCMV). To test the effect of UV treatment, the delivery of the pp65 virion protein to the cells and the synthesis of the IE1 and IE2 immediate-early proteins were monitored. UV irradiation did not affect viral entry into the cells because the amount of pp65 delivered to the cells did not change with UV treatment (Fig. 1A). The IE1 and IE2 proteins were detected at 8 and 21 h after infection in HCMV-infected cells, but not in UV HCMV-infected cells (Fig. 1 A). Inhibition of viral RNA accumulation in UV HCMV-infected cells was also evident. The IE1 transcript could be detected at 8 h after infection in HCMV-infected cells, but not in UV HCMV-infected cells (Fig. IB). We also determined the location of a virion protein in cells infected with UV-treated virus. pp65 was visible in nuclei at 2 h after infection with either HCMV or UV HCMV (Fig. 1C, panel 1 and 2). As expected, IE1 protein was detected in HCMV-infected but not in UV HCMV- infected cells (Fig. 1C, panel 3 and 4). These experiments demonstrate that UV irradiation of virus particles blocked the accumulation of detectable amounts of HCMV-encoded RNA without preventing the entrance of the virus into the cell or altering the intracellular localization of a virion protein.

We compared RNA levels by differential display (16, 17) at 8 h after infection or mock infection. HCMV immediate-early proteins have accumulated to significant levels at this time (see Fig. 5), giving them an opportunity to influence host cell mRNA accumulation. PCR-generated bands that were evident in virus-infected but not mock-infected samples could be divided into two groups. One group contained an induced band that was present in the HCMV-infected sample, but not in the UV HCMV-infected sample. The induced bands in this group could be derived from either viral or cellular RNAs. The second group contained induced bands in both HCMV- and UV HCMV-infected samples. These bands should represent cellular RNAs that accumulate after HCMV infection, since viral mRNAs are not produced in UV HCMV-infected cells (Fig. IB).

We selected 71 of the most strongly induced PCR-generated bands for analysis. These DNA fragments were reamplified by PCR, cloned, and used as probes for Northern blot analyses to confirm that the bands represented differentially expressed genes. Examples of these assays are displayed in Figure 2A. Most of the cloned cDNA segments identified RNAs that were present at very low or non- detectable levels in mock-infected cells, but accumulated to a high level in infected cells. cDNA clones representing up-regulated RNAs were isolated from 57 of the 71 reamplified fragments. Each clone is termed a cig for CMV /nducible gene.

Thirty of 57 cig RNAs were induced by HCMV but not UV HCMV infection, and sequence analysis revealed that all of these clones corresponded to viral RNAs (data not shown). Two of the viral RNAs were produced after infection in the presence of cycloheximide identifying them as immediate-early RNAs, and the synthesis of the remainder was inhibited by the drug, indicating that they are early RNAs (Fig. 2B and data not shown).

Infection with either HCMV or UV HCMV led to the accumulation of 27 of the 57 cig RNAs, and sequence analysis demonstrated that they correspond to as many as 15 different cellular genes (Table 1). Nine were previously identified, and the other 6 were not found in a BLAST search. Surprisingly, most of the known RNAs previously were shown to be induced by interferon-α in HF cells, as were the 6 new RNAs (Fig. 2C and data not shown). The RNAs were induced both by virus infection and interferon-α in three lots of HF cells derived from different individuals (data not shown). Since the RNAs induced by infection corresponded to interferon-inducible genes, it seemed possible that other interferon-stimulated genes might be induced by HCMV. As expected, RNAs corresponding to mxA (33, 34), ISG15K (35, 36) and interferon-β (37) also were induced (Fig. 2C). As controls, we tested the expression of p53, p21 , cytosolic phospholipase A2 (cPLA2) and actin. The level of these RNAs did not change after infection (Fig. 2D and Fig. 5). Table 1. Cellular cDNA clones identified by differential display analysis

Clone Gene Reference

cig 1, 22, 51 interferon-stimulated gene 54K 24 cig 19 KIAA0062 25 cig 24, 70 glyceraldehyde-3-phosphate dehydrogenase 26 cig 25 guanylate binding protein isoform I 27 cig 32 Mn-superoxide dismutase 28 cig 34, 45, 46, 68 microtubular aggregate protein, p44 29 cig 43 IFP53 30 cig 52 (2'-5') oligoadenylate synthetase 31 cig 53 guanylate binding protein isoform II 32 cig 5-7, 15, 18, 44, 61, 69 new this patent cig 33 new this patent cig 41 new this patent cig 42 new this patent cig 49 new this patent cig 64 new this patent

EXAMPLE 5 HCMV particles induce the accumulation of cig RNAs encoded by cellular genes. The differential display analysis utilized the laboratory adapted AD 169 strain of HCMV. Towne, a second laboratory adapted HCMV strain, and Toledo, a low passage clinical isolate of HCMV, also strongly activated the accumulation of cell-coded cig RNAs (Fig. 3 A, lane 10 and 11). Wild-type adenovirus did not activate the accumulation of cig RNAs and HSV-1 increased their expression to a very limited extent (Fig. 3 A, lanes 8 and 9; Fig. 5). The expression of an adenovirus and HSV-1 mRNA was monitored to be certain that cells were successfully infected (data not shown). Thus, whereas multiple HCMV strains strongly induced cig RNA accumulation, two other viruses did not.

To ask if cellular protein synthesis was required for the induction of cellular interferon-responsive RNAs, cells were infected in the presence of cycloheximide. It did not block the induction of cig RNAs by HCMV, and the drug itself had no effect on cig RNA expression (Fig. 3A, lane 4 and 5). This result indicates that the accumulation of cig RNAs does not require the synthesis of viral or cellular proteins after infection. It also rules out the possibility that a protein factor, such as a cytokine, is synthesized in response to the infection, and released from the cell so that it can interact with a cell surface receptor to induce cig RNAs.

Because infected cell lysates were used as virus stocks in our initial experiments, it was possible that soluble signaling molecules were present that could mediate the induction of RNAs encoded by the cell. We therefore performed a series of experiments to identify the component in HCMV stocks that was responsible for the induction. Initially, an HCMV stock was separated into two fractions by filtration through a 100 kDa cutoff membrane. The virus fraction was further purified by rate-velocity centrifugation, separating infectious virions and non- infectious enveloped particles (NIEPs, lacking viral DNA). The filtered lysate, purified virions and NIEPs were used to treat cells, and their abilities to induce the accumulation of cig RNAs were assayed. Purified virions and NIEPs activated cig RNA accumulation (Fig. 3A, lane 6 and 7), while the filtered lysate had little effect (Fig. 3A, lane 3). To prove that small molecules could pass through the filter, interferon-α (500 U/ml) was added to the infected cell lysate, and there was no loss of interferon activity after filtration (Fig 3 A, lane 13 and 14).

We used neutralizing antibodies to confirm our observation indicating that the activation of cig RNA accumulation is mediated by HCMV particles and not by interferon. When the virus stock was incubated with antibody to virions, its ability to induce cig RNAs was blocked, while antibody to interferon-α or β had no effect (Fig. 3B). The same amounts of interferon-specific antibodies were sufficient to block interferon-α or β activity in uninfected cultures (Fig 3B). We conclude that the HCMV particle or a molecule tightly associated with the particle initiates the induction of cellular cig RNAs. Expression of viral gnes is not required, since purified NIEPs and UV HCMV can induce cig RNAs.

We next explored the possibility that interferon might be carried within the HCMV particle. Purified viral particles were treated with Triton X- 100 (0.5%) and deoxycholate (0.5 %) and subjected to centrifugation to produce a supernatant fraction containing HCMV membrane proteins and a pellet containing internal virion constituents. With detergent treatment, pp65 (a marker for the tegument/capsid fraction) was in the pellet fraction and gB (a marker for the membrane fraction) was in the supernatant fraction. Without detergent treatment, the particle remained intact, and both pp65 and gB were in the pellet fraction (data not shown). As expected, without detergent treatment, the pellet fraction, but not supernatant fraction, activated cig RNA accumulation; with detergent treatment, neither the pellet fraction, nor supernatant the fraction activated the accumulation (Fig. 4A). When interferon-α was treated with the detergent mixture, its activity was not affected (Fig. 4A). This experiment indicates that the intact virus particle is required for the induction of cig RNAs, and further argues that this induction is not due to contaminating interferons.

Our results argue that the induction of cell-coded cig RNAs does not result from contaminants in HCMV preparations or from newly synthesized signaling proteins. Nevertheless, one might propose that a trace amount of a signaling molecule is stored in the cell, secreted after infection, and then acts at the surface of neighboring cells to induce cig RNAs. Accordingly, we performed an experiment in which uninfected cells and cells infected 1 h earlier were mixed in a ratio of 9: 1, and a sufficient number of cells were plated to generate a confluent monolayer. At the same time, 100% infected cells or 100% non-infected cells were plated at the same density. RNA was prepared at 8 h after infection, and the expression of cig RNAs and the HCMV IE1 RNA were assayed. The viral and cig RNAs were induced in the infected culture, but not in the uninfected culture (Fig. 4B). The RNA levels were induced to the same extent in the mixed culture as was seen for an uninfected/infected (ratio, 9: 1) cell mixture prepared immediately before the extraction of RNA (Fig. 4B). Infected cells did not significantly induce the accumulation of cig RNAs in their uninfected neighbors.

EXAMPLE 6 Kinetics of cig RNA induction by HCMV as compared to interferon-α. The kinetics of cig RNA accumulation varied when cells were treated with different inducers (Fig. 5). Accumulation was first evident at 4-6 h after infection with HCMV, cig RNA levels peaked at about 8 h, and remained at high levels for the duration of the experiment (48 h). The HCMV IE1 gene showed a similar expression pattern. The induction of cig RNA expression in cells treated with interferon-α was more rapid and transient. The cig RNAs were detected at 30 min and reached their peak at 2-4 h before declining rapidly. The marked difference in the kinetics of cig RNA accumulation in HCMV-infected as compared to interferon-treated cells further supports the conclusion that the induction observed subsequent to HCMV infection is not the result of contaminating interferon in virus preparations.

In HSV-1 -infected cells, the induction of cig RNAs was very limited (Fig. 5), consistent with the view that the strong induction of cig RNA accumulation observed in HCMV-infected cells is not a common cellular response to all herpesviruses. As a control, the HSV-1 icp47 immediate-early gene was shown to be expressed at a high level, demonstrating that the culture was successfully infected. Discussion We cloned 57 partial cDNA segments corresponding to RNAs that are present at a higher concentration in HCMV-infected as compared to mock-infected human fibroblasts. The 57 clones represent no more than 26 different mRNAs because some of the RNAs corresponded to more than one cDNA fragment generated by different primer sets. It is possible that we have identified fewer than 26 distinct RNAs since 6 of the partial cellular cDNAs were not found in a BLAST search, and we have determined the complete sequence of only one of the newly discovered RNAs. Since the others are only partially sequenced, more than 1 of the remaining 5 sequences might be contained within the same RNA molecule. However, only 2 of the 5 partially sequenced clones appear tσ recognize RNAs of identical size in Northern blot assays (Fig. 2 and data not shown).

Of the 26 cDNA clones, 11 were virus-coded. All of the immediate-early and some early HCMV mRNAs should have accumulated to detectable levels at 8 h after infection when cells were harvested; and partial cDNA clones corresponding to both classes of viral RNA were isolated . The screen identified 2 from a total of approximately 10 immediate-early mRNAs. One can not accurately estimate the total number of HCMV early mRNAs expressed at 8 hr since the number increases continually from about 4 h to 24 h after infection (15). Given the uncertainties about the number of different viral mRNAs present in the cells, it is difficult to estimate accurately the proportion of HCMV RNAs that were identified in the differential display analysis. However, since we identified 2 of about 10 immediate-early mRNAs, it seems likely that the screen identified substantially less than half of the viral mRNAs that were present, even though multiple clones were isolated that corresponded to several of the viral transcripts. Partial cDNA clones corresponding to the most abundant immediate-early (IE1/IE2: ref. 38, 39) and early (TRL4: ref. 40) mRNAs were isolated, so our screen might have favored the identification of the more plentiful species. Given the proportion of immediate-early viral mRNAs that were identified in the screen, it seems likely that we also identified substantially less than half of the cellular RNAs that were induced at 8 h after infection. Nevertheless, multiple partial cDNA clones corresponding to some of the cellular transcripts were isolated (Table 1, supra). In fact, 8 overlapping clones were isolated that corresponded to one of the cellular RNAs whose sequence was not found in a BLAST search.

All of the cellular RNAs that were induced at 8 h after infection proved to be interferon-inducible (Table 1 and Fig. 2C). We presume that they are induced by HCMV infection at the level of transcription as is the case when their accumulation is induced by interferon, but we have not yet determined this. A complete cDNA corresponding to one of the interferon-inducible RNAs {cig 49) has been cloned and sequenced. It is related to ISG54K (24). One of the partial cDNA sequences (c/g42) also appears to be related to ISG54K, and the other 4 are not related in their primary sequence to known genes.

We were concerned that the cellular RNAs identified in the screen might be induced by interferon or another contaminant of the virus preparations, but a variety of observations argue that the induction is mediated by virus particles. The most direct evidence supporting this view derives from neutralization experiments (Fig. 3B), and the timing of the induction is not consistent with a role for interferon (Fig. 5). Further, it is unlikely that the induction involves a cytokine or small molecule other than interferon in the virus preparations since the inducing activity fractionated with the virions (Fig. 3A). We have ruled out the possibility that interferon or another signaling molecule is synthesized by infected cells and secreted to act at the cell surface, since the interferon-responsive mRNAs are induced in the presence of cycloheximide (Fig. 3A). Finally, experiments in which infected cells were mixed with uninfected cells (Fig. 4B) argue that pre-existing stores of a signaling molecule are not released after infection with HCMV to act at the cell surface and initiate a signal cascade. A constituent of the virus particle, rather than a viral gene product synthesized after infection, mediates the induction because UV-irradiated particles that fail to express immediate-early mRNAs (Fig. 1) can sponsor the accumulation (Fig. 2A). We are currently working to identify the inducer and its mode of action.

Three different strains of HCMV strongly induced the accumulation of interferon response RNAs (Fig. 3A), and the AD 169 strain was shown to induce these RNAs in HF cells prepared from three different tissue samples (data not shown). Adenovirus did not induce and HSV-1 generated a very weak induction (Fig. 3 A and 5). Thus, the relatively strong HCMV-mediated induction is not a general feature of infection by DNA viruses. Adenovirus has been shown to block the induction of interferon response genes through the action of its El A proteins (41- 43). However, an ElA-deficient adenovirus mutant, dl312 (21), also failed to induce the genes (data not shown). In contrast, HSV-1 has been shown to induce the production of interferon-α in human peripheral mononuclear cells (44-46). So the weak induction observed in HSV-1 -infected HF cells might result from a direct induction of interferon-responsive genes, from the production of double-stranded RNA which can induce the genes or from the initial induction of interferon-β with a subsequent general induction of interferon-response genes as the secreted interferon acts at the cell surface. Besides the strength of induction, the HSV-1- and HCMV-mediated reactions differ in another important respect. HCMV induces interferon-response mRNAs very early during its replication cycle in HF cells (Fig. 5), beginning about 20 h prior to the onset of viral DNA replication. In contrast, the induction observed for HSV-1 occurs later during its more rapid replication cycle (47).

Does HCMV lack the means to prevent the accumulation of interferon-inducible genes or does it somehow exploit their induction? Perhaps HCMV, in contrast to some other viruses, has not evolved the means to block the induction of interferon- inducible mRNAs. The anti-viral actions of the induced cellular products could be antagonized by viral products at a post-transcriptional level, or HCMV might activate these genes as part of a strategy to slow and minimize the extent of its replication within an infected host. Such a strategy, together with the ability to undergo latency could facilitate the long term association of the pathogen with its host. It is also possible that the virus utilizes a component of the interferon- response pathway to activate its own genes.

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Claims

WHAT IS CLAIMED IS:

1. A set of human genes, the expression of which, is specifically modulated by human cytamegalovirus (HCMV) and limited to the following: a) genes that are induced to express by both HCMV and interferon, designated HCMV-/nducible genes {cig or cigs); and, b) genes that repressed in the presence of HCMV infection, designated HCMV-repressible genes {erg or ergs).

2. A cig of Claim 1 which is a cDNA having a nucleotide sequence selected from the group consisting of SEQ ID NOS. l , 3, 5, 7, 9, 11, 13, 15, 17, 19, 21-26, 28, 30, and 32.

3. A cig of Claim 1 which is a polypeptide having an amino acid sequence selected from the group consisting of SEQ ID NOS:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 27, 29, 31, and 33.

4. A erg of Claim 1 which is a cDNA having a nucleotide sequence selected from the group consisting of SEQ ID NOS:34, 36, 38, and 39.

5. A erg of Claim 1 which is a polypeptide having an amino acid sequence selected from the group consisting of SEQ ID 35, and 37.

6. A DNA sequence that hybridizes to any of the nucleotide sequences of Claim 2 or 4, and degenerate varients thereof.

7. A recombinant DNA molecule comprising a DNA sequence of Claim 2 or 4, and degenerate variants thereof.

8. The recombinant DNA molecule of either of Claim 7, wherein said DNA sequence is operatively linked to an expression control sequence.

9. The recombinant DNA molecule of Claim 8, wherein said expression control sequence is selected from the group consisting of the early or late promoters of SV40 or adenovirus, the lac system, the trp system, the TAC system, the TRC system, the major operator and promoter regions of phage ╬╗, the control regions of fd coat protein, the promoter for 3 -phosphogly cerate kinase, the promoters of acid phosphatase and the promoters of the yeast ╬▒-mating factors.

10. A probe capable of screening for the cigs or ergs in alternate species prepared from the DNA sequence of Claim 6.

11. A unicellular host transformed with a recombinant DNA molecule comprising a DNA sequence or degenerate variant thereof, which encodes a cig or erg gene product, or a fragment thereof, selected from the group consisting of SEQ ID NOS: l, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21-26, 28, 30, 32, 34, 36, 38, and 39, wherein said DNA sequence is operatively linked to an expression control sequence.

12. The unicellular host of Claim 11 wherein the unicellular host is selected from the group consisting of E. coli, Pseudomonas, Bacillus, Streptomyces, yeasts, CHO, Rl. l, B-W, L-M, COS 1 , COS 7, BSC1, BSC40, and BMT10 cells, plant cells, insect cells, and human cells in tissue culture.

13. A method for detecting the level of expression of cig or erg mRNAs consisting of:

A. capture probes, based on the sequences of Claim 6, immobilized onto a solid support; B. contacting a biological sample containing cig and erg mRNAs from a human or human cell culture with the capture probes under standard hybridization conditions; and,

C. detecting the levels of hybridization that has occured between the target mRNAs and the capture probe; wherein the levels of hybridization detected reveals the levels of expression from the cigs and ergs of Claim 1.

14. The method of Claim 13 used as a screening assay to identify drugs or compounds that alter the expression of cig or erg mRNAs, and are thus candidates for anti-viral or anti-HCMV drugs.

15. The method of Claim 13 used as a diagnostic assay to evaluate the efficacy of a treatment regimen for HCMV or other viral infections.

16. An antibody to a polypeptide sequence of Claim 3 or 5.

17. The antibody of Claim 16 which is a polyclonal antibody.

18. The antibody of Claim 16 which is a monoclonal antibody.

19. An immortal cell line that produces a monoclonal antibody according to Claim 18.

20. The antibody of Claim 16 labeled with a detectable label.

21. The antibody of Claim 20 wherein the label is selected from enzymes, chemicals which fluoresce and radioactive elements.

22. An antisense nucleic acid against a cig mRNA comprising a nucleic acid sequence hybridizing to said mRNA.

23. The antisense nucleic acid of Claim 22 which is RNA.

24. The antisense nucleic acid of Claim 22 which is DNA.

25. The antisense nucleic acid of Claim 22 which binds to the initiation codon of any of said mRNAs.

26. A recombinant DNA molecule having a DNA sequence which, on transcription, produces an antisense ribonucleic acid against a cig mRNA, said antisense ribonucleic acid comprising an nucleic acid sequence capable of hybridizing to said mRNA.

27. A cig gene product-producing cell line transfected with the recombinant DNA molecule of Claim 26.

28. A method for creating a cell line which exhibits reduced expression of a cig mRNA, comprising transfecting a cig mRNA-producing cell line with a recombinant DNA molecule of claim 26.

29. A ribozyme that cleaves cig mRNA.

30. The ribozyme of Claim 29 which is a Tetrahymena-type ribozyme.

31. The ribozyme of Claim 29 which is a Hammerhead-type ribozyme.

32. A recombinant DNA molecule having a DNA sequence which, upon transcription, produces the ribozyme of claim 29.

33. A cig mRNA-producing cell line transfected with the recombinant DNA molecule of claim 32.

34. A method for creating a cell line which exhibits reduced expression of a cig mRNA, comprising transfecting a cig mRNA-producing cell line with the recombinant DNA molecule of claim 29.

35. A rg gene product (protein) used as a n anti-viral or anti-HCMV therapeutic.

36. A cig gene product (protein) used in conjunction with interferon therapy to reduce toxicity of said interferon and thus allow administration of higher doses of said interferon.