Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/68—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
  • G01N33/6893—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids related to diseases not provided for elsewhere
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
  • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
  • A61K47/62—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being a protein, peptide or polyamino acid
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P3/00—Drugs for disorders of the metabolism
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
  • C07K14/435—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
  • C07K14/46—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from vertebrates
  • C07K14/47—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from vertebrates from mammals
  • C07K14/4701—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from vertebrates from mammals not used
  • C07K14/4722—G-proteins
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K16/00—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies
  • C07K16/18—Immunoglobulins [IG], e.g. monoclonal or polyclonal antibodies against material from animals or humans
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/53—Immunoassay; Biospecific binding assay; Materials therefor
  • G01N33/575—Immunoassay; Biospecific binding assay; Materials therefor for cancer
  • G01N33/5758—Immunoassay; Biospecific binding assay; Materials therefor for cancer involving compounds serving as markers for tumours, cancers or neoplasias, e.g. cellular determinants, receptors, heat shock/stress proteins, A-protein, oligosaccharides or metabolites
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
  • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
  • G01N33/68—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving proteins, peptides or amino acids
  • G01N33/6872—Intracellular protein regulatory factors and their receptors, e.g. including ion channels
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K38/00—Medicinal preparations containing peptides

Definitions

• a second messenger is one that activates an appropriate cellular response to a specific external signal. It becomes activated when the receptor stimulated by an external signal excites an internal molecule, e.g., an enzyme, which in turn stimulates the production of a second messenger substance.
• G-proteins are a class of regulatory proteins which bind guanosine di- and triphosphate nucleotides, i.e., GDP and GTP, respectively.
• the family of G-proteins serves as peripherally membrane-bound signal transducing polypeptides, coupling activation of cell surface receptors to the regulation of intracellular effectors. These proteins can activate the enzymatic abilities of adenylate cyclase or a phosphodiesterase while binding GTP.
• G-proteins examples include G s and Gi, which are responsible for the regulation of adenylate cyclase; transducin, which activates a cGMP-specific phosphodiesterase in the retina; ADP-ribosylation factor (ARF) in the liver (Kahn et al. -L. Biol. Chem. 25_9_:6228-6234, 1984); and P21, the product of the ras protooncogene. (For a review, see Whitman et al., Phosphoinositides and Receptor Mechanisms, copyright 1986 by Alan R. Liss, Inc., pp. 197-217).
• a second signal transduction system serves as a basis for cellular signalling by mitogenic growth factors such as growth hormone (GH), platelet-derived growth factor (PDGF), epidermal growth factor (EGF), and radiation of specific wavelengths.
• GH growth hormone
• PDGF platelet-derived growth factor
• EGF epidermal growth factor
• This system involves various intermediates in the inositol metabolic pathway. It employs calcium ions and a combination of second messengers ultimately derived from phosphatidylinositol (PI), which is a minor plasma membrane constituent.
• PI phosphatidylinositol
• an external signal such as light in the photoreceptor cell, activates a receptor, e.g., rhodopsin, which then, by means heretofore unknown, stimulates the catalytic activity of phospholipase C.
• a key event with regard to the second messenger function is the hydrolysis of an inositol derivative, phosphatidylinositol 4,5-biphosphate (PIP2), a minor membrane constituent, by phospholipase C (PL-C) to yield inositol-1,4,5- triphosphate (IP3) and diacylglycerol (DG) .
• PIP2 phosphatidylinositol 4,5-biphosphate
• IP3 inositol-1,4,5- triphosphate
• DG diacylglycerol
• Both of these reaction products act as second messengers in at least two different systems: DG controls ion currents through the membrane by regulating membrane permeability to various ions and the activity of protein kinase C; while IP3 regulates the concentration of intracellular Ca +2 which in turn affects many cellular processes, e.g., cell division and proliferation.
• the elucidation of the regulatory mechanism involved in the inositol-related signal transduction system will provide a better understanding of the disease states which result from its dysfunction, and can lead to the development of preventative and/or compensatory measures. More specifically, there exists a need for methods of treating disease states resulting from the dysfunction of this system, and for methods of regulating inositol metabolism in cultured cells and cells of higher organisms.
• compositions of matter that can link cell membrane receptors with the inositol-related signal transducing system, thus enabling the manipulation of the inositol metabolic pathway to compensate for disease states resulting from its dysfunction. It is also an object of the invention to provide a method of regulating the metabolic pathway in a cell.
• novel bioactive compositions including an A-protein, which stimulate, inhibit, or normalize cellular metabolism, in particular the inositol pathway.
• the inositol metabolic pathway in a cell can be sensitized by introducing a signal transducing molecule into that cell, e.g., by means of a synthetic lipid vesicle or liposome.
• the inositol pathway may be stimulated by the introduction of preactivated A-protein, e.g., an A-protein-GTP conjugate, preferably comprising a non-hydrolyzable GTP analog, e.g., a commercially available material such as GTP-gamma-S or GMPPNP.
• the molecule useful in these methods of the invention has the ability to functionally couple an activated membrane-bound receptor to a phosphodiesterase, which then becomes enzymatically active.
• the phosphodiesterase is the enzyme responsible for- generating a second messenger that causes a cellular response.
• the signal transducing molecules useful in the foregoing methods of the present invention are isolated and purified A-proteins, active fragments of an A-protein, active A-protein analogs, and active fusion products and derivatives thereof. Incubation of these materials with non-hydrolyzable GTP analogs, or other complexes of the two, provide inositol metabolism stimulants.
• A-protein was originally used to describe rod photoreceptor protein of approximately 20 kilodaltons molecular weight. Improved extraction and separation methods combined with preliminary sequence data on the separated forms indicates that the entity referred to previously as A-protein may consist of at least two structurally and functionally related proteins; one membrane-bound and one soluble. On this basis, the terminology used reflects the presumed is vivo state: A m , membrane bound (19 kD); and A s , soluble (20 kD) . These A-proteins include the amino acid sequences set forth in the Sequence Listing as SEQ ID NO:l (A m ) and SEQ ID NO:2 (A s ).
• A-protein related molecules for the practice of the invention, are that they comprise a single polypeptide chain with a significantly hydrophobic region. These molecules also have the ability to bind and hydrolyze guanosine nucleotides adenosine and guanosine triphosphate, and have the ability to activate phospholipase C and other phospholipases in the presence of GTP.
• Native A-proteins may be recovered from known and available cells, e.g., photoreceptor cells of the eye, and many other cell types. Native A-proteins can be obtained in purities greater than 80% from vertebrate photoreceptors and other types of cells using the methods disclosed below. The stability of A-protein in aqueous suspension is enhanced by the addition of nonionic detergents.
• the present invention provides a method of stimulating the proliferative abilities of a cell.
• This method comprises the step of introducing into the cell a signal transducing molecule as characterized above conjugated with a non-hydrolyzable analog of GTP.
• cell proliferation can be inhibited by introducing an antibody which recognizes, binds, and inactivates the signal transducing molecule, as characterized above, or by introducing a non-functional A-protein analog.
• the present invention provides methods for controlling secondary effects of diabetes, including vascular degeneration and slowed nerve conduction, for reducing the intracellular concentration of GTP, and for regulating the level of calcium ions in a cell. These methods comprise introducing into the cells of a subject a signal transducing molecule as characterized above.
• the invention also provides novel compositions of matter, useful for stimulating the inositol metabolic pathway in a cell, and for promoting cell proliferation, consisting of an A-protein, an active fragment, analog, or fusion product thereof, coupled to a non-hydrolyzable GTP analog, e.g., guanosine-5'-0-[3 thiotriphosphate] or ⁇ - ⁇ -imidoguanosine 5' triphosphate.
• GTP analog e.g., guanosine-5'-0-[3 thiotriphosphate] or ⁇ - ⁇ -imidoguanosine 5' triphosphate.
• This invention also includes a method for detecting an A-protein in a biological sample.
• a first antibody which binds to a first epitope on an A-protein is adhered to a solid support.
• the first antibody is contacted with the biological sample to be tested.
• a labeled second antibody which binds a second epitope on an A-protein is then added to the solid support.
• This second antibody further comprises a marker. Any unbound antibody is removed, and the presence or absence of the marker is then detected, its presence being indicative of the presence of A-protein in the sample.
• the antibodies of the present invention may also be used to inhibit the growth and proliferation of cancer cells.
• these antibodies may also be used to image (in vivo and in vitro) a cell, tissue, or organ that has an A-protein present on its surface. This requires the administration of an antibody specific for a membrane-bound form of A-protein (A m ) conjugated to a detectable marker to the cell, tissue, or organ in a pharmacologically acceptable vehicle. The presence or absence of the marker on the cell, tissue, or organ is then determined, its detection or presence being indicative of the presence of A-protein.
• a m membrane-bound form of A-protein
• FIG. 1 is a schematic representation of the known inositol lipid metabolic pathway that yields second messengers IP3 and DG, supplemented to show the function of A-proteins;
• FIG. 6 is a photographic representation of the purification of the A m and A s forms of the A-protein by SDS-PAGE. The gel was stained with silver. Lane 1 is purified A m ; lane 2 is purified A s ; and lane 3 shows molecular weight standards;
• FIG. 8 is a graphic representation of the ATPase activity of purified A m and A s combined (1:2) and reconstituted with 32p-ATP and washed ROS membranes and incubated in light or dark conditions;
• FIG. 9 is a graphic representation of the binding of GTP-analog GMP-PNP by soluble and membrane-bound forms of A-protein in the presence of adenosine nucleotides.
• FIG. 10 is a graphic representation of the ATPase activity of A s and A m in presence of GTP ⁇ S. DESCRIPTION OF THE INVENTION
• a cell's inositol metabolism may be inhibited by the introduction of a nonfunctional A-protein analog which competes with the native form upon stimulation of a receptor.
• a truncated form or analog of an A-protein which retains the ability to bind GTP and/or to couple with a receptor, but lacks the ability to activate PL-C inhibits inositol metabolism when introduced into a cell.
• Antibodies against A-proteins bind and inactivate them, thus also inhibiting inositol metabolism and reducing or terminating the effect of receptor stimulation. Intracellular administration of such a non-functional analog or antibody can inhibit cell mitosis.
• A-proteins have been isolated from mammalian (bovine) and amphibian (frog) rod outer segments (ROS) by extraction, centrifugation, chromatography and other protein purification techniques known to those skilled in the art. See U.S. Patent Application Serial No. 170,737, the disclosure of which is herein incorporated by reference. Other proteins with similar or identical physical and functional characteristics as the A-proteins have been isolated from various other tissues from vertebrates and invertebrates. These findings indicate that the structure of the A-proteins has been conserved through evolution.
• the present invention is based on the recognition that the A-proteins have a universal regulatory role in cells which employ inositol-type metabolism.
• A-proteins are quite labile in aqueous solution, but can be significantly stabilized if disposed in aqueous solutions containing a nonionic surfactant. Theyt have a molecular weight in the range of 20 to 21 kD, as inferred by comparison to molecular weight standards during electrophoretic separations.
• A-proteins, various truncated or mutein analogs thereof, and fused proteins comprising an A-protein and other protein domains can be produced by various synthetic and biosynthetic means.
• an appropriate host cell such as a microorganism, yeast, or eucaryotic cell culture can be genetically engineered to express an A-protein, or a portion or analog thereof. This may be accomplished by now well established recombinant DNA technologies known to those skilled in the art.
• the recombinant procedure may include the isolation or synthesis of a gene encoding an A-protein, a portion, or analog thereof, and the integration of that gene into a plasmid.
• the amino acid sequences of the A-proteins may be established readily given this disclosure.
• Sequence Listing sets forth the N-terminus amino acid sequence of two forms of A-protein (A s and A m ) as SEQ ID NO:l and SEQ ID NO:2.
• Gene synthesis from synthetic oligonucleotides and known mutagenesis techniques provide the technologies to prepare an array of analogs, truncated A-protein forms, and fused proteins comprising A-protein or a domain thereof. Production of such materials further may include the transformation of an appropriate host cell with a vector harboring the recombinant DNA, culturing that transformed host cell, and isolation of the expressed protein. Given the availability of A-protein-rich samples producible as disclosed herein, the recombinant production of the native form and various analogs thereof is well within the current skill in the art.
• At least portions of the protein may be produced synthetically by chemically biasing amino acids in the correct sequence.
• the antibody-marker complex may be prepared by chemical linkage or by recombinant DNA techniques if the marker is proteinous.
• the antibodies may be labelled with a reagent which enables the monitoring of the antibody after its administration to a patient.
• the label may be, for example, a radioisotope such as 125- or 99m-- C/ both of which may be imaged extracorporeally by radiation detection means such a gamma scintillation camera.
• An anti-A-protein monoclonal antibody can be obtained from a hybridoma cell line formed upon the fusion of a mouse myeloma cell with a spleen cell of a mouse previously immunized with an A-protein purified, for example, from bovine ROS.
• the immunogen alternatively can be a derivative of A-protein, or an analog or portion thereof, produced in vitro according to known mechanical or manual procedures of peptide synthesis.
• the immunogen (A-protein) can be synthesized by biosynthetic means using recombinant DNA technologies known to those skilled in the art.
• the mice whose spleen cells are chosen for fusion are preferably from a genetically defined lineage such as Balb/c.
• mice used for producing antibodies in this way are sacrificed after a defined period, and the antibody is harvested from the ascites fluid. Under normal circumstances, mice survive for two to four weeks after infusion. Of the four different hybridomas injected into 40 mice, all caused an apparent immune response in the host animal. The animals all died prematurely with significantly enlarged spleens and lymph nodes as well as generalized edema. Post-mortem examination revealed no tumors in any of the mice.
• a failure of the immune system can be one component in the establishment of tumor cells.
• a treatment that both checks cancerous growth and recruits a directed autoimmune response to the tumor is thus effective in causing regression of neoplastic tissues.
• anti-A-protein antibodies will affect normal tissues as well as neoplastic growth, it is necessary to ensure that the antibodies are directed to the target cells. This becomes particularly important if the antibodies attract an immune response from the host. The better localized the response, the more effective it may be. in addition, the antibodies may cause related autoimmune problems if they are generalized in the blood stream.
• One way to specifically deliver agents to cancer tissue is to package the antibodies in carriers such as synthetic lipid vesicles, or liposomes, that are coated with a different antibody which specifically binds to cancer cells.
• the liposome fuses with the outer membrane of the cancer cell and the contents are disgorged into the cell.
• A-proteins or antibodies thereto, conjugates, or analogs thereof may be administered, via the use of a protective and directive vehicle such as liposomes, to a subject afflicted, for example with cancer, diabetes, retinitis pigmentosa, etc., or to a cell culture to stimulate or depress inositol metabolism.
• a protective and directive vehicle such as liposomes
• Liposomes contacting a cell membrane can deposit their contents into the cell via endocytosis.
• Liposomes useful for this purpose can be prepared by any number of methods (e.g., Bangham et al. (1965) _ ⁇ _. Mol. Biol. 11:238-252; Deamer and Bangham (1976) Biochem. Biophys.
• porous plastic discs preloaded with anti-A-protein antibody, an A-protein, an A-protein conjugate, or analog thereof, into the site of the lesion.
• This technology is already used for site-specific drug delivery and recent advances in the technology now make it possible to use large macromolecules in combination with the discs.
• Any other localized delivery system e.g., microcapsules or polymeric agents, could similarly be used.
• compositions of the types described above have a number of utilities, both in vitro and in vivo.
• the introduction of the native or of active analog forms of A-proteins into cells having an overabundance of GTP, or expressing a defective form of a native A-protein, can reduce intracellular GTP concentration and restore or improve inositol metabolism.
• Activated A-protein conjugates can stimulate inositol metabolism, leading to cell replication.
• introduction of such conjugates into the cells of a transformed or non-immortal cell culture can produce a pulse of replication.
• Non-functional A-protein conjugates and antibodies to A-protein can depress inositol metabolism, and thus mitosis, in, for example, malignant cells.
• Bovine (cow or calf) eyes were obtained from a local abattoir within 2 hours of killing. Bovine eyes were kept on ice in the dark for 30 to 60 minutes.
• Retinas were dissected out and placed in buffer A (130 mM NaCl, 20 mM Tris-HCl, pH 7.0; 1 ml per calf retina or 2 ml per cow retina).
• buffer A 130 mM NaCl, 20 mM Tris-HCl, pH 7.0; 1 ml per calf retina or 2 ml per cow retina.
• gentle, repeated inversions of the container liberated large numbers of ROS into the buffer.
• the mixture was poured through a Buchler funnel to remove the retinas.
• the filtrate was allowed to settle in a conical-bottomed tube on ice for 5 minutes, allowing gross particulate matter to settle out of the ROS suspension.
• the supernatant is found, by means of microscopic examination on a hemocytometer, to consist of greater than 95% ROS.
• the ROS were disrupted with shear created by repeatedly drawing the suspension into the syringe and forcing it out against the wall of the container.
• the suspension was centrifuged at 10,000 to 12,000 x g for 20 minutes at 4°C.
• the pellet containing ROS membranes was washed once with a volume of buffer A equal to that of the removed supernatant.
• the resulting pellet was resuspended in 3 to 6 ml of buffer T (0.05%) Tween 20/80 (1:1) in double-distilled water) and spun at 15,000 x g for 45 minutes.
• T 0.05%) Tween 20/80 (1:1) in double-distilled water
• Both A-protein solutions were filtered through Centricon 30 microconcentrators (molecular weight cut-off of 30 kD, Amicon Corporation), with centrifugation at 5,000 x g in a refrigerated centrifuge. The ultrafiltrates were then concentrated and dialyzed in Centricon 10's (molecular weight cut-off of 10 kD) at 5,000 x g.
• A-proteins purified by ultrafiltration as described above were further purified for sequence analysis by HPLC on a Bio-Sil SEC-125 column in buffer A (A s ) or buffer T (A m ) . Elution was isocratic. Pooled peaks were concentrated, dialyzed against water and lyophylized prior to analysis.
• a s purified by ultrafiltration as described was run on a HPLC size exclusion column (TSK-2000, Bio-Rad) in buffer A (FIG. 5A), and then rechromatographed in 0.1 M potassium phosphate buffer on a DEAE anion-exchange column. Protein was eluted with a 0 to 200 mM NaCl gradient (FIG. 5B) .
• A-proteins differs markedly in aqueous solution.
• a m is metastable in the purified state and retains most of its functional properties for several days at 4°C. A can also withstand freezing and thawing in detergent without losing more than 15 to 20% of its original activity.
• a s is labile under a variety of conditions and no satisfactory methods of treatment have been found to prevent greater than 80% activity loss over a 48 hour period at 4°C.
• Polyacrylamide gel electrophoresis was performed according to a modification of the methods of O'Farrell (_I. Biol. Chem. (1975) _25JL:4007) in the presence of 0.1% SDS in a pore gradient gel (10 to 20%). Samples were applied in a sample buffer of 0.33 mM DTT, 7% SDS, 17% glycerol and 0.5 M Tris-HCl, pH 6.8, and run to equilibrium. Samples were not heat-denatured, in order to avoid the appearance of additional bands caused by the formation of stable polymers. Proteins were visualized with the Bio-Rad silver stain kit. Gels were calibrated using pre-stained molecular weight standards from Bio-Rad (range 17 to 94 kD) .
• A-protein includes A m , a membrane bound form having a molecular weight of about 19 kD and A s , a soluble form having a molecular weight of about 20 kD.
• the soluble protein resolves into two closely spaced bands on gels.
• the membrane-bound form migrates ' as a single band.
• FIG. 7 also shows a comparison of the initial amino acid sequences of As, bovine retinal ARF (brARF) protein, bovine adrenal ARF (baARF) protein, and the H, K, AND N ras ⁇ 21 proteins.
• the stripped, radiolabelled ROS membranes (50 ⁇ l) were recombined with 30 ⁇ l of A-protein (5-8 ⁇ g) solution and the cytosolic PL-C-containing fraction in buffer B which contained 1 mM GTP, 1 mM ATP, and 0.01% nonionic surfactant. The final volume of each sample was 200 ⁇ l.
• control samples containing either no A-protein, no PL-C, or none of either were prepared to check the PL-C solution and ROS membranes for background activity.
• Samples were either exposed to a bright 10 msec xenon flash (Nikon) (delivering 1.8 x 10 3 ⁇ Wcm ⁇ 2 sec ⁇ l) sufficient to bleach greater than 70% of the rhodopsin present in each sample or kept in the dark as control. Both dark and light samples were simultaneously quenched with 200 ⁇ l of ice cold 15% trichloroacetic acid immediately following the light flash (within 10 seconds) . Following quench, the samples were kept on ice for 30 minutes. Samples were spun down in a microcentrifuge for 5 minutes and 100 ⁇ l of supernatant was aliquoted for liquid scintillation counting.
• FIG. 2 shows the radioactivity, represented as counts per minute (cpm), recovered in the aqueous phase of ROS membrane, prelabelled with tritiated myoinositol, and reconstituted with purified A-protein and the phospholipase C ROS fraction. Bars in FIG. 2 marked “L” represent samples exposed to a xenon flash; samples represented by “D” were kept dark. The bars on the right in the drawing are for identical samples without the A-protein and hence depict background.
• cpm counts per minute
• ROS suspension Two milliliters of ROS suspension were prepared from 10 bovine retinas, as described in EXAMPLE 1, above, as previously described. The suspension was mixed with a five-fold excess of chloroform-methanol (2:1) and allowed to stand on ice for 1 hour. The mixture was spun briefly and the lower phase was removed with a pipette. This lower phase (-2 ml) was removed and washed once with 3 milliliters of chloroform-methanol-0.2 N HCl
• This solution contained - 1 ⁇ M lipid/ml.
• Liposomes were prepared according to the method of Ghalayini and Anderson Q3iochem. Biophys. Res. Cornm. (1984) 414:503-506). Purified A-protein and A-protein-free PL-C fractions were prepared as described previously. 3 H-PIP2 (L-al ⁇ ha-[myo-inositol- 2- 3 H(N)]) phosphatidylinositol; New England Nuclear, Boston, MA) was incorporated into stripped ROS membranes, prepared as described above, by means of liposomes. 3 H-PIP2 (0.5 ⁇ Ci) was dried under N2 after being mixed with lipids extracted from ROS.
• 3 H-PIP2 ⁇ labeled ROS membranes (100 ⁇ l) were combined with purified A-proteins (5 to 10 mg), and A-protein-free PL-C fraction in a buffer.
• the buffer contained 20 mM Tris, pH 7.0, 1 mM ATP, 0.25 mM GTP and 0.05 mM GMPPNP ( ⁇ - ⁇ -imidoguanosine 5'-triphosphate) (Sigma Chemical Co., St. Louis, MO), a non-hydrolyzable GTP analog. Each sample had a final volume of 300 ⁇ l.
• Control samples were made up as above except that either the A-proteins or PL-C or both were deleted. Identical samples, including control samples, were either kept dark or exposed to room light for 30 minutes. Aliquots of each sample (100 ⁇ l) were removed at 1, 10, and 30 minutes of the incubation and quenched with an equal volume of ice-cold 15% trichloroacetic acid. Quenched samples were kept on ice for 30 minutes and then spun for 5 minutes in a microcentrifuge. 100 ml of the supernatant of these samples was assayed for radioactivity by liquid scintillation counting.
• FIG. 3 graphically shows counts per minute of released radioactivity for samples subjected to light (L) and for samples that remained dark (D), with background response being subtracted.
• the samples containing activated A-protein and PL-C were the only ones to demonstrate significant levels of PIP2 hydrolysis.
• the A-protein-containing "light” sample showed 24% of the available radioactive PIP2 had been hydrolyzed.
• This activation of PIP2 hydrolysis is direct evidence of PL-C activation by A-protein, since PIP2 has been shown to be the specific and only substrate of PL-C.
• the greater release of radioactivity in the light-exposed sample compared to the "dark" sample is a demonstration that this process is receptor mediated.
• Hybridomas were produced by fusion of spleen cells from the sacrificed mouse with NS-1 (P3NS-1/1-Ag4-1) myeloma cells (American Type Culture Collection, Rockville, MD; Accession No. TIB18) .
• NS-1 P3NS-1/1-Ag4-1) myeloma cells
• Nadakavukaren Differentiation 22:209-202, (1984) was employed to perform the fusions.
• Resultant clones were tested for binding to A-protein. Subcloning by serial dilution was carried out on one clone.
• the most productive subclones were injected into the peritoneal cavity of Balb/c mice to produce ascites fluid containing monoclonal antibody. The ascites fluid which is obtained is centrifuged, tested for activity, and then stored at -70° C until required.
• the resulting 18 anti-A-protein antibodies were screened for antibody isotype by the Ouchterlony double diffusion test in agar plates against anti- IgM, anti-IgG, anti-IgGl, anti-IgG2a, anti-IgG2b, and anti-IgG3 antibodies (Cappell) .
• the results are shown in TABLE 1
• CRL 1747 grown to confluency in flasks of MEM (10% fetal bovine serum, 12% penicillin- streptomycin, 0.1% fungamycin; incubated at 5% CO2) were plated out at low density into 2 mm culture dishes. These cells were used because they contain an activated H-ras oncogene.
• Liposomes were used to introduce the anti-A-protein antibodies into the cells by fusion. These liposomes were prepared by drying down 100 ml negatively charged lipid (L- ⁇ -phosphatidylcholine, dicetyl phosphate, and cholesterol, in a molar ratio of 63:18:9) in a glass tube, and adding 1 ml of IgG solution (or 1 ml pH 7.4 buffer, in the case of
• empty liposomes had increased by 34%, but the cells treated with immunoliposomes containing IgG has been reduced to 66% of the original cell count.
• the control cell population was 400% of the original, the cells treated by empty liposomes had increased to 225% of the original population, whereas the cells treated by the anti-A-protein IgG had further decreased to 38% of the original population.
• Balb/c mice (1 or 9 weeks old, both sexes) were immunosuppressed on arrival by injection of 0.2 ml Pristane. 12 days later, hybridoma cells (raised initially in Balb/c mice, then grown in flask cultures) which had been spun down into phosphate buffered saline (PBS) were administered by intraperitoneal injection (4 x 10 6 cells per 1 week old mouse) .
• PBS phosphate buffered saline
• 4C5F3 was also introduced to 9-week-old (adult) mice, to see how much, if any, difference the age of the subject makes. Controls were not injected.
• mice All trial injections of myeloma hybridomas into mice were run in multiples and in parallel with controls. Propositus and control mice were all immunosuppressed with pristane prior to treatment. Mice from the second study were enucleated and the retinas were sectioned to examine the rod outer segments for damage.
• mice injected with hybridomas were uniformly damaged at the level of the rod outer segments beginning as early as day 2. This damage appeared to involved disruption of the outer segment membranes and occasionally extended partially into the inner segments. Damage was completely confined to the photoreceptor cells. Disruption was occasionally severe enough to cause retinal detachment.
• mice showed the presence of small numbers of hybridoma tumors or detectable levels of myeloma-like cells in the ascites fluid. Descriptions of these individuals are as follows:
• the 4C5F3 mouse exhibited less of an immune reaction than the 3F5H11 mouse that died overnight. Some tumor deposits were visible on the peritoneal wall, and food was found in the gastrointestinal tract: this is the more usual reaction to injection of monoclonal antibody cells to the peritoneal cavity of mice; normally the cells grow in the ascites fluid as tumors. It is a common means of propagating monoclonal antibody cell lines. The remaining mice left in each group were sacrificed on day 10. The 7E4F9 mouse had a swollen abdomen, and almost 4 milliliters of fluid was removed from its cavity. There was an immune reaction, and the lymph nodes were swollen to visibility.
• the 3A7G6 mouse exhibited a more normal reaction, in that its abdomen was not swollen, food was present in the tract, little fluid was found in the cavity (1 milliliter), the lymph nodes were not swollen, and small tumors were present.
• Purified mAb to A-protein (100 to 200 ⁇ g) was preincubated with purified A-protein (50 to 100 ⁇ g) for 30 minutes prior to the experiment. Stripped ROS, partially purified phospholipase C, 3 H-PIP2 vesicles (0.1 ⁇ Ci; 0.022 ⁇ g PIP2/sample), GTP ⁇ S (final concentration is 100 ⁇ mol/sample), and the mAb/A-protein mixture (about 10 ⁇ g mAb; about 5 ⁇ g A-protein/sample) were combined with buffer (10 mM Tris-HCl, 10 mM KCL, pH 7.4) to a final volume of 300 ⁇ l/sample. A sample without antibody was used as control.
• the rate of hydrolysis of GTP or ATP by both soluble and membrane-bound A-protein was assayed in a total volume of 200 ⁇ l. 1.0 to 10.0 ⁇ g A m , 5 x 10 ⁇ 5 M GTP or ATP, 67 to 335 nM [ ⁇ " 32 P] GTP or 88.8 to
• the rate of GTP hydrolysis by A m (0.458 GTP sec ⁇ l/A m ) is comparable to that of transducin (0.512 GTP sec ⁇ -/T ⁇ ) when both are measured at submaximal velocity in the presence of photoactivated rhodopsin.
• the GTPase rates for A m and transducin are additive when the two purified proteins are present in approximately equimolar concentrations.
• a m and A s were found to have ATPase activity that was not receptor coupled.
• the K m values for both A m and A s ATPases are given in TABLE 4, above. Comparison of the rate constants of A m indicates that its affinity for ATP is approximately an order of magnitude greater than that of A s .
• the relative K m values for GTPase and ATPase activity of both A and A s indicate that GTP is the preferred substrate for binding and hydrolysis.
• the samples were vortexed and incubated at 25 ⁇ C for 30 minutes, quenched with 200 ⁇ l ice-cold buffer (0.5 M NaCl, 0.1 M Tris-HCl, 0.1% Tween 80), and kept on ice for 30 minutes.
• the samples were placed onto nitrocellulose filters that had been previously washed with 2 ml of the same buffer. The filters were rinsed 5 times with 2 ml ice-cold buffer and assayed for radioactivity.
• adenosine nucleotides The effect of adenosine nucleotides on the binding of Gpp(NH)p to a mixture of A m and A s was examined because of the ability of the A-proteins to bind and hydrolyze ATP.
• Purified A m and A s were mixed (1:2), preincubated with ATP or ADP, and assayed for Gpp(NH)p binding after a brief incubation by the rapid filtration method.
• ATP was an effective inhibitor of binding at all concentrations tested.
• ADP was inhibitory in a concentration-dependent manner at higher concentrations.
• Protein concentrations were determined according to Bradford (Anal. Biochem. (1976) 22:248), using the Bio-Rad Microassay (Coomassie Brilliant Blue G-250) . Bovine serum albumin was used as a standard.
• the complement of A m relative to A s is 0.47.
• the ratio of the amounts of the separated soluble species recovered from high pressure columns (as estimated by optical density at 280 nm) and slab gels (as estimated by densitometry) is approximately unity. This indicates that all forms of A-protein are extracted in equivalent amounts from rods if the two soluble forms are the products of separate genes. If not, the membrane-bound form would thus be present at half the concentration of the soluble.
• the monoclonal antibodies produced against A-protein were used to create an assay for the detection of that antigen in the serum of humans.
• the procedure employs an enzyme-linked immunosorbent assay (ELISA) .
• ELISA type of ELISA being used in this context is of the "sandwich” variety. This assay requires two different antibodies that are specific for A-protein, but which each recognize and -57-
• One of the antibodies serves as the "capture” agent and is used unmodified to coat the bottom of a chamber in a standard 96-well microtiter plate.
• the antibody is then removed from the well and a blocking agent (1% bovine serum albumin (BSA)) is then placed in the chamber to block non-specific binding sites.
• BSA bovine serum albumin
• Serum from the propositus is then incubated in the prepared well for from 1 to 12 hours, and then removed.
• the well is washed with a detergent solution, and the second antibody in solution is added to the well.
• the second antibody used in this procedure is physically linked to an enzyme; in this case the enzyme used is horseradish peroxidase (HRP). Following this incubation, the second antibody is removed and the well is washed once more.
• the final step consists of adding an appropriate colorimetric substrate.
• the amount of color development is directly proportional to the amount of enzyme-linked antibody bound in the well, which is proportional to the amount of antigen bound in the well by the "capture" antibody.
• the results are quantitated by a spectrophotometric determination of the amount of color produced over a predetermined period of time (typically 30 to 120 minutes) . -58-
• the ELISA described above has been used to test human serum from normal healthy volunteers, cancer patients, and individuals with diagnosed bacterial infections, for the presence of the A-protein antigen.
• the normal population was used to determine the threshold of positivity in this assay.
• the sensitivity of the assay extends at least to the single ng/ml range as determined by the construction of standard sensitivity curves using known amounts of purified antigen.
• a positive reaction in the test was obtained from patients diagnosed with lung, lymphoma, stomach, colon, rectal, and breast cancer when compared to normal subjects.
• a positive reaction in the test was also obtained from individuals with a diagnosed bacterial infection, when compared to normal subjects, including both intestinal and venereal sites.

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