WO2003100426A1

WO2003100426A1 - Diagnostic indicator of sjögren's syndrome

Info

Publication number: WO2003100426A1
Application number: PCT/US2003/016103
Authority: WO
Inventors: Thomas L. Brown; Jon S. Morrow
Original assignee: Wright State University; Yale University
Priority date: 2002-05-20
Filing date: 2003-05-20
Publication date: 2003-12-04
Also published as: AU2003233635A8; AU2003233635A1

Abstract

A method of identifying primary and secondary Sjögren's Syndrome or susceptibility to developing primary and secondary Sjögren's Syndrome in a subject is provided. The method includes obtaining a biological sample from the subject, contacting the sample with a purified target antigen, wherein the target antigen is an epitope of beta II spectrin, and detecting the presence of autoantibodies in the sample which bind to the target antigen. The presence of the autoantibodies is indicative of the presence of primary or secondary Sjögren's Syndrome in the subject or the susceptibility to developing primary or secondary Sjögren's Syndrome in the subject compared to subjects lacking autoantibodies that bind to the target antigen. A diagnostic kit, a pharmaceutical composition, and a method of treating or delaying the pathological effects of primary and secondary Sjögren's Syndrome in a patient are also provided, each employing beta II spectrin or a fragment thereof.

Description

DIAGNOSTIC INDICATOR OF SJOGREN'S SYNDROME

The present invention relates to autoimmune disease and, more particularly, to a method of identifying primary and secondary Sjogren's Syndrome or susceptibility to developing primary and secondary Sjogren's Syndrome in human patients and/or animal models.

Sjogren's Syndrome is a chronic human autoimmune disease that affects between 0.5 and 5.0% of the world population (see Manthrope R., et al., Epidemiology of Sjogren's syndrome, especially in its primary form. Ann. Med. Interne (Paris) 149:7-11 (1998)), in which the moisture-producing glands such as, for example, the salivary and lacrimal glands, are damaged with an accompanying autoimmune response (e.g., by apoptosis). This results in the patient's inability to produce saliva or tears. In addition to dry mouth that can make chewing, swallowing, and speaking difficult, and dry eyes that can lead to corneal ulcers and sometimes blindness, the disease can affect several other parts of the body causing muscle weakness, joint pain, confusion and memory problems, dry skin, feelings of numbness and tingling, as well as heightened chances for developing cancer of the lymph tissue. Further, Sjogren's Syndrome may result in functional problems of the vital organs such as the lungs, kidneys, or liver. Sjogren's Syndrome can appear in primary and secondary forms. The primary form appears by itself, wherein only the salivary and lacrimal glands are affected. Secondary Sjogren's Syndrome occurs in conjunction with other autoimmune diseases such as rheumatic diseases including rheumatoid arthritis, systemic lupus erythematosus, polymyositis, and/or sclerosis.

The causes of Sjogren's Syndrome are not known and present methods for clinically diagnosing the disease are lengthy, expensive, and based on a number of factors that cannot be considered reliable indicators. Moreover, diagnosis of Sjogren's Syndrome almost always comes after pathological effects are evident and the salivary and lacrimal glands have been destroyed. Presently, there is no known cure for Sjogren's Syndrome, and known treatment regimens are limited to alleviating discomfort and lessening the symptoms associated with the disease, i.e., dryness.

Accordingly, there is a need for a method that provides for early detection of Sjogren's Syndrome, including detection prior to the occurrence of glandular tissue damage, as well as the identification of therapeutic agents for the induction of immune tolerance in patients with the disease. These needs are met by the present invention that employs beta II spectrin protein (i eta-fodrin, non-erythroid spectrin), and fragments thereof, as tools for detecting the presence of autoantibodies in the serum and other bodily fluids or tissues of patients suspected of having Sjogren's Syndrome.

Although the present invention is not limited to specific advantages or functionality, it is noted that the method provides for early detection of the disease before the pathological effects have set in and, therefore, enables preventative treatment to prolong salivary and lacrimal function. In one embodiment of the present invention, a method of identifying primary and secondary Sjogren's Syndrome or susceptibility to developing primary and secondary Sjogren's Syndrome in a subject is provided comprising obtaining a biological sample from the subject, contacting the sample with a purified target antigen, and detecting the presence of autoantibodies in the sample which bind to the target antigen, wherein the presence of the autoantibodies is indicative of the presence of primary or secondary Sjogren's Syndrome in the subject or the susceptibility to developing primary or secondary Sjogren's Syndrome in the subject compared to subjects lacking autoantibodies that bind to the target antigen. The target antigen is an epitope of beta II spectrin.

In another embodiment of the present invention, a diagnostic kit for detection of autoantibodies associated with primary and secondary Sjogren's Syndrome in a biological sample is provided comprising a substrate including an identifying antigen bound on a surface of the substrate and at least one reagent for detection of the autoantibodies in the biological sample. The identifying antigen comprises a purified beta II spectrin protein or a fragment thereof, to which the autoantibodies bind.

In still another embodiment of the present invention, a pharmaceutical composition is provided comprising at least one purified ligand of beta II spectrin protein or a fragment thereof and a pharmaceutically acceptable buffer, solvent, diluent, adjuvant, or carrier.

In yet another embodiment of the present invention, a method of treating or delaying the pathological effects of primary and secondary Sjogren's Syndrome in a patient is provided comprising administering a therapeutic or prophylactic amount of a pharmaceutical composition comprising at least one purified ligand of beta II spectrin protein or a fragment thereof in association with a pharmaceutically acceptable carrier. These and other features and advantages of the present invention will be more fully understood from the following description of the invention taken together with the accompanying figures. It is noted that the scope of the claims is defined by the recitations therein and not by the specific discussion of features and advantages set forth in the present description. Fig. 1 is a photograph of beta II spectrin protein that was bacterially expressed and purified on a glutathione agarose matrix;

Fig. 2 is a photograph of purified beta II spectrin protein that was tested for serum reactivity by Western blotting; and

Fig. 3 is a photograph of a microtiter plate coated with purified beta II spectrin protein and analyzed for serum reactivity.

Spectrin is a filamentous contractile protein that together with actin and other cytoskeleton proteins forms a network giving certain vertebrate cells their size and shape. Both the alpha and beta subunits of this protein share a homologous internal 106 amino acid repeating motif called a spectrin repeat. (See Kuwana M, et al., Autoantibodies to the amino-terminal fragment of β-fodrin expressed in glandular epithelial cells in patients with Sjogrens syndrome. J. Immunol. 167:5449-5456 (2001)). However, befa-fodrin has additional amino- and carboxyl-terminal regions with no homology to a/pΛa-fodrin. (See id. at 5449 (citing Hu, R.-J., et al., Characterization of human brain cDNA encoding the general isoform of β-spectrin. J. Biol. Chem. 267:18715 (1992)).

Beta II spectrin, in particular, is genetically distinct from alpha II spectrin, and is a cytoskeleton protein of 235 kilodaltons (kDa). (See Morrow JS, et al., Of membrane stability and mosaics: the spectrin cytoskeleton. Handbook of

Physiology. J. Hoffman and J. Jamieson (Eds.), London, Oxford 485-540 (1997)). The appearance of an N- or amino-terminal fragment of beta II spectrin, 65 kDa in size, can be mediated by caspase-3 or granzyme B. (See Wang KK, et al., Simultaneous degradation of all- and βll-spectrin by caspase 3 (CPP32) in apoptotic cells. J. Biol. Chem. 273:22490-7 (1998); and Kuwana M, et al., supra). Autoantibodies reactive with a 65 kDa fragment of beta II spectrin on Western blots can be found in the serum of patients exhibiting the pathological effects of Sjogren's Syndrome. (See Kuwana M, et al., supra). This indicates that patients with Sjogren's Syndrome may produce an autoantibody to a protein fragment of j efa II spectrin.

Beta II spectrin protein or a construct thereof, a mutant thereof, a glutathione S-transferase (GST) purified or other forms of purification protein fragment thereof, or a salt thereof, which can be used in the present invention, includes but is not limited to human beta II spectrin protein. There is no limitation on biological species or molecular weight of the beta II spectrin protein, provided that it is immunochemically equivalent to human beta II spectrin protein or any fragment thereof. By "immunochemically equivalent" we mean that the protein or protein fragment is biologically indistinguishable in antibody reactivity and antigenicity and is thus recognizable by the same antibody or serum containing autoantibodies to beta II spectrin.

The cDNA sequence that encodes the beta II spectrin protein has been determined. Knowledge of this particular nucleotide sequence has enabled the development of the diagnostic indicator and the therapeutic agents of the present invention, which are useful in the diagnosis, monitoring, and treatment of Sjogren's Syndrome. Whereas a particular nucleotide sequence (SEQ ID NO. 1 ) and its corresponding translated amino acid sequence (SEQ ID NO. 2) of mouse beta II spectrin is disclosed herein, other sequences that encode for beta II spectrin protein are also encompassed by the present invention, i.e., different cDNA sequences encoding for the same amino acid sequence. These sequences can include the nucleotide sequences of beta II spectrin derived from the tissues or cells of other warm-blooded animals, i.e., bovine, porcine, ovine, etc. The cDNA molecule described herein need not be complete in order to be useful, so long as the protein encoded thereby retains specificity to beta II spectrin autoantibodies.

In accordance with a preferred embodiment of the present invention, a diagnostic indicator is provided which can determine whether a patient is at risk, has early signs, or is affected by Sjogren's Syndrome. The diagnostic indicator is an assay, which can be packaged as part of a diagnostic kit. The assays will detect the presence of autoantibodies to beta II spectrin in normal serum, as well as other bodily fluids such as urine and saliva, or tissues from patients suspected of being at risk for primary Sjogren's Syndrome. The indicator is also an effective diagnostic for secondary Sjogren's Syndrome in patients with systemic lupus erythematosus and other associated autoimmune diseases.

It has been found that a high percentage of patients exhibiting the pathological effects of Sjogren's Syndrome produce an autoantibody to a protein fragment of beta II spectrin. (See Kuwana M, et al., supra). Consequently, the preferred assay of the present invention will be able to detect the presence of antibodies reactive with beta II spectrin by utilizing beta II spectrin protein (beta- fodrin, non-erythroid spectrin), as well as segments or peptides of beta II spectrin. A positive result will indicate that the patient is at risk, has early signs, or is affected by Sjogren's Syndrome and provides a useful tool for the diagnosis and/or confirmation of the disease. By providing early diagnosis of Sjogren's Syndrome, the present invention is effective in accelerating and/or altering the course of preventative treatment regimens, which prolong salivary and lacrimal function in these patients. Moreover, the diagnostic indicator of the present invention has application in monitoring disease progression in human patients and animal models, such as in clinical trials.

The inventors do not wish to restrict the use of the present invention to the diagnosis of Sjogren's Syndrome in human patients. It is therefore contemplated that the present invention has application in animal model systems of the disease. Assays according to the preferred embodiment of the present invention typically rely on exposing purified beta II spectrin protein or fragments thereof to a sample (i.e., serum) and detecting specific binding between the purified protein and autoantibodies to beta II spectrin, which may be present in the sample. Binding between the purified protein or fragment indicates that the autoantibodies are present, and is diagnostic of acute Sjogren's Syndrome in the patient.

Assays according to the preferred embodiment of the present invention will also be useful for identifying patients who are at risk or are in the early stages of Sjogren's Syndrome (i.e., who have circulating autoantibodies to beta II spectrin protein but have not yet suffered significant damage to the salivary and lacrimal glands to be clinically identified as having Sjogren's Syndrome), or who suffer from the pathological effects of the disease. As noted above, the assay can further be used to monitor the development of the disease in Sjogren's Syndrome positive patients.

Suitable assays include both solid phase (heterogeneous) and non-solid phase (homogeneous) protocols. The assay may be run using competitive or non-competitive formats, and using a wide variety of labels, such as radioisotopes, enzymes, fluorescers, chemiluminescers, spin labels, and the like. A majority of suitable assays rely on heterogeneous protocols where the purified protein or fragment is bound to a solid phase that is utilized to separate the protein-autoantibody complex, which forms when autoantibody is present in the serum or other body fluid or tissue sample. A particular advantage of using a purified protein or fragment thereof is that it facilitates the preparation of a solid phase for use in the assay. That is, the protein or fragment may be conveniently immobilized on a variety of solid phases, such as dipsticks, particulates, microspheres, magnetic particles, test tubes, microtiter wells, and the like. The solid phase is exposed to the sample so that the autoantibody, if any, is captured by the purified protein or fragment. By then removing the solid phase from the sample, the captured autoantibodies can be removed from unbound autoantibodies and other contaminants in the sample. The captured autoantibody may then be detected using the non-competitive "sandwich" technique where labeled proteins or fragments for the autoantibody are exposed to the washed solid phase. Alternatively, competitive formats rely on the prior introduction of soluble, labeled autoantibody to the sample so that labeled and unlabelled forms may compete for binding to the solid phase. Such assay techniques are well known and well described in both the patent and scientific literature. Exemplary immunoassays, which are suitable for detecting the autoantibodies in serum, include those described in U.S. Pat. Nos. 3,791 ,932; 3,817,837; 3,839,153; 3,850,752; 3,850,578; 3,853,987; 3,867,517; 3,879,262; 3,901,654; 3,935,074; 3,984,533; 3,996,345; 4,034,074; and 4,098,876, the disclosures of which are incorporated herein by reference.

Particularly preferred are sensitive enzyme-linked immunosorbent assay (ELISA) methods, which are described in detail in U.S. Pat. Nos. 3,791 ,932; 3,839,153; 3,850,752; 3,879,262; and 4,034,074. Such ELISA assays can provide measurement of very low titers of the autoantibodies and therefore permit even earlier detection of Sjogren's Syndrome.

According to the preferred ELISA technique, the purified protein or fragment is bound either covalently or non-covalently to a solid surface. The solid surface is exposed to the serum sample where autoantibody present in the sample is captured and bound. Typically, the protein or fragment on the solid phase will be present in excess so that the entire quantity of autoantibody may be bound. After separating the solid phase and washing its surface, the solid phase can be exposed to labeled reagent capable of specifically binding the captured autoantibody. The labeled reagent may be labeled purified protein or fragment, or may be other protein or fragment capable of binding to the autoantibody, e.g., labeled anti-human antibody. In this way, label is bound to the solid phase only if autoantibody was present in the sample. The enzyme labels may be detected by conventional visualization techniques, i.e., production of a colored dye, chemiluminescence, fluorescence, or the like.

A second preferred embodiment comprises radioimmunoassays (RIA) that are performed using a solid phase, which has been prepared as described above. The solid phase is exposed to the sample in the presence of radiolabeled autoantibodies, which can compete for binding to the immobilized protein or fragment. In this way, the amount of radiolabel bound to the solid phase will be inversely proportional to the amount of autoantibodies initially present in the sample. After separation of the solid phase, non-specifically bound radiolabel can be removed by washing, and the amount of radiolabel bound to the solid phase determined. The amount of bound radiolabel, in turn, can be related to the amount of autoantibodies initially present in the sample.

In accordance with another aspect of the invention, the beta II spectrin protein or fragment thereof can be comprised of a ligand defining an all-spectrin peptide or a chimeric peptide containing beta II spectrin epitopes. The ligand can be included in a pharmaceutical composition that could be useful to attenuate, inhibit, or prevent the destruction of glandular tissue (i.e., salivary and lacrimal glands) that is associated with the onset of Sjogren's Syndrome. The compositions should contain a therapeutic or prophylactic amount of at least one purified ligand according to the present invention in a pharmaceutically-acceptable carrier. The pharmaceutical carrier can be any compatible, non-toxic substance suitable to deliver the peptides to the patient. Sterile water, alcohol, fats, waxes, polymers, and inert solids may be used as the carrier. Pharmaceutically- acceptable adjuvants, enhancers, buffering agents, dispersing agents, matrix, and the like, may also be incorporated into the pharmaceutical compositions. Such compositions can contain a beta II spectrin protein or fragment thereof, a single polypeptide encoded by the beta II spectrin gene, or may contain two or more polypeptides according to the present invention in the form of a "cocktail". Although not intending to be limited to any particular theory, further contemplated is the addition of small molecules or other bio agent(s) that could interfere in the recognition and binding of the autoantibodies with at least one ligand of the beta II spectrin protein or fragment thereof, and thereby at least impede the degradation of the disease-targeted tissue.

The pharmaceutical compositions just described are useful for both parenteral and topical administration. Preferably, the compositions will be administered parenterally (i.e., subcutaneous, intramuscular, or intravenous) or topically (e.g., transdermal, transmucosal, or topical gel). Thus, the invention provides compositions for administration to a patient, where the compositions comprise a solution or dispersion of the polypeptides in an acceptable carrier, as described above. The concentration of the beta II spectrin protein or fragment thereof or polypeptides in the pharmaceutical composition can vary widely, i.e., from less than about 0.1 % by weight, usually being at least about 1 % by weight, to as much as about 20% by weight or more. A typical pharmaceutical composition for intramuscular injection could contain, for example, 1ml of sterile buffered water and 1 to 100μg of the purified ligand of the present invention. A typical composition for intravenous infusion could contain, for example, 100 to 500ml of sterile Ringer's solution and 100 to 500mg of the purified ligand. Actual methods for preparing parenterally administrable compositions are well known in the art and are described in more detail in various sources, including, for example, Remington's Pharmaceutical Science, 15th Edition, Mack Publishing Company, Easton, Pa. (1980), which is incorporated herein by reference.

The pharmaceutical compositions comprising the beta II spectrin protein or fragment thereof of the present invention may be administered for prophylactic treatment of individuals identified by the assay methods of the present invention, or for therapeutic treatment of individuals suffering from Sjogren's Syndrome. For therapeutic applications, the pharmaceutical compositions are administered to a patient suffering from established Sjogren's Syndrome in an amount sufficient to inhibit or prevent further destruction of the salivary and lacrimal glands. For individuals susceptible to Sjogren's Syndrome, the pharmaceutical compositions are administered prophylactically as part of a novel strategy to induce hi-dose tolerance in autoimmune individuals, or in an amount sufficient to activate dendritic cells so as to tolerize T-cells to beta II spectrin epitopes, and thereby suppress autoimmunity to beta II spectrin and either prevent or inhibit immune destruction of the salivary and lacrimal glands. (See Hackstein H, et al., Designer dendritic cells for tolerance induction: guided not misguided missiles. Trends Immunol. 22:437-42 (2001 )).

In order that the invention may be more readily understood, reference is made to the following examples, which are intended to illustrate the invention, but not to limit the scope thereof.

METHODS

Expression and Purification of Beta II Spectrin by GST (1-313 AA)

A single colony of transformed bacteria was inoculated into 50ml LB broth (with 50μg/ml ampicillin) and grown overnight at 37°C in a shaking incubator. The overnight cultures were diluted with 10 vol. of fresh media and grown to an optical density of 1.0 at OD of 600nm. Protein expression was then induced for 4 hours by addition of IPTG (isopropylthiogalactoside) into the culture medium (final concentration 1mM).

For purification, bacterial cells were harvested by centrifugation and resuspended in 1/50 original culture volume of 50mM Tris-HCI, 50mM NaCI, 1mM EDTA, 1mM DTT, and protese inhibitors. Lysozyme (1mg/ml final) and Triton X- 100 (1% final) were added, and the cultures were incubated for 30 minutes at 4°C with gentle agitation. The cultures were then diluted in an additional 1/50 of original culture volume in the above buffer, sonicated and centrifuged at 20,000 rpm for 20 minutes. The supernatant fraction, containing the soluble proteins, was purified on preswollen glutathione agarose matrix. Purification was verified by embedding the protein in 10% acrylamide gel and Coomasie blue staining. Lanes 1 and 3 include the purified beta II spectrin protein and lane 4 includes the molecular weight standard (see Fig. 1).

Briefly, the agarose beads and the supernatant were incubated in an end- over-end rotator for 1 hour at 4°C. Approximately 2ml of preswollen beads were used per bacterial preparation. After binding, the beads were washed several times with PBS and the protein eluted in 1ml fractions with 50mM Tris-HCI, 1mM EDTA, 1mM DTT containing 5mM reduced glutathione. The eluted protein was analyzed on SDS-PAGE by coomasie blue staining and used subsequently in Western blot analysis and in ELISA.

Western Blot Analysis Beta II spectrin protein purified by glutathione S-transferase ("beta II spectrin-GST") was tested for serum reactivity by Western blotting. A 5μg sample of the purified beta II spectrin-GST protein was resolved by SDS-PAGE gel and electrophoretically separated and transferred onto a polyvinylidene fluoride ("PVDF") membrane. The membrane was incubated for 1 hour in blocking buffer (phosphate-buffered saline containing 0.05% Tween 20 and 5% nonfat dry milk) followed by 2 hour incubation with primary antibody in blocking buffer. After extensive washing, the blot was incubated with secondary antibody for 1 hour and processed using the Renaissance chemiluminescence reagent. The membrane was subjected to human anti-sera from Sjogren's Syndrome positive and negative individuals. Lane 1 included Sjogren's Syndrome positive serum and lane 2 included Sjogren's Syndrome negative serum (see Fig. 2).

Enzyme-Linked Immunosorbent Assay (ELISA)

Flat bottomed Dynex Immunolon 1B microtiter plates were used as solid- phase absorbents. The conditions were optimized prior to sample analysis. Beta II spectrin-GST fusion protein was diluted to 20μg/ml with coating buffer (NaHCO₃) and 50μl of the sample was added to 96-well plate for overnight incubation at 4°C. The plate was washed three times, 5 min. with washing buffer, and subsequently blocked for 1 hour with blocking buffer (5% nonfat, dry milk) at room temperature.

The serum samples were diluted 1/1000 in blocking buffer. 50μl of diluted serum was added to the wells and incubated at room temperature for 1 hour. The plates were washed as described above and subsequently incubated with 50μl of 1/5000 dilution of goat anti-human horseradish peroxidase IgG for 30 minutes at room temperature. The plate was the washed described as above, 50μl of substrate ABTS was added/well, and the plate was incubated in 37°C for 30 minutes. Results were obtained by reading at A405 on a VMAX ELISA reader.

CONCLUSIONS

An ELISA assay was optimized for analysis of serum reactivity against beta II spectrin. This assay is effective as a diagnostic tool for early detection of Sjδgren's Syndrome. Because the current diagnosis of Sjogren's Syndrome is an end stage, this protocol provides an opportunity to initiate treatment of the disease in the sub-clinical cases.

Fig. 3 is a photograph of a microtiter plate that was coated with purified beta II spectrin and analyzed for serum reactivity. Lanes 1-4 contain random serum samples, lane 5 contains Sjogren Syndrome positive serum, and lane 6 contains Sjogren Syndrome positive serum.

While the invention has been described by reference to certain preferred embodiments, it should be understood that numerous changes could be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the disclosed embodiments, but that it have the full scope permitted by the language of the following claims.

Claims

CLAIMS 1. A method of identifying primary and secondary Sjogren's Syndrome or susceptibility to developing primary and secondary Sjogren's Syndrome in a subject comprising: obtaining a biological sample from said subject; contacting said sample with a purified target antigen, wherein said target antigen is an epitope of beta II spectrin; and detecting the presence of autoantibodies in said sample which bind to said target antigen, wherein the presence of said autoantibodies is indicative of the presence of primary or secondary Sjogren's Syndrome in said subject or the susceptibility to developing primary or secondary Sjogren's Syndrome in said subject compared to subjects lacking autoantibodies that bind to said target antigen.

2. The method of claim 1 , wherein said subject is a human.

3. The method of claim 1 , wherein said biological sample is a bodily fluid selected from serum, urine, saliva, or combinations thereof.

4. The method of claim 1 , wherein said target antigen is of human, animal, synthetic or recombinant origin.

5. The method of claim 1 , wherein said target antigen is a beta II spectrin protein.

6. The method of claim 5, wherein said beta II spectrin protein is selected from constructs, mutants, purified fragments, peptides, and salts of beta II spectrin protein.

7. The method of claim 6, wherein said purified fragment of said beta II spectrin protein is a 65 kDa amino-terminal fragment generated through cleavage by caspase-3 or granzyme B.

8. The method of claim 1 , wherein said autoantibodies are detected by a labeled reagent that binds to said autoantibodies.

9. The method of claim 1 , wherein said target antigen is bound to a solid phase reagent.

10. The method of claim 1 , wherein said autoantibodies are detected by an assay selected from an enzyme-linked immunosorbent assay, a radioimmunoassay, an immunofluorescence assay, or a Western blot.

11. The method of claim 1 further comprising monitoring the development of primary and secondary Sjogren's Syndrome in subjects possessing said autoantibodies which bind to said target antigen.

12. A diagnostic kit for detection of autoantibodies associated with primary and secondary Sjogren's Syndrome in a biological sample comprising: a substrate including an identifying antigen bound on a surface of said substrate, wherein said identifying antigen comprises a purified beta II spectrin protein or a fragment thereof; and at least one reagent for detection of said autoantibodies in said biological sample, wherein said autoantibodies bind to said identifying antigen.

13. The diagnostic kit of claim 12, wherein said biological sample is a bodily fluid selected from serum, urine, saliva, or combinations thereof.

14. The diagnostic kit of claim 12 further comprising labeled animal anti-human immunoglobulin.

15. The diagnostic kit of claim 14, wherein said labeled animal anti-human immunoglobulin is goat anti-human horseradish perioxidase IgG.

16. The diagnostic kit of claim 12, wherein said substrate is used in a method selected from an enzyme-linked immunosorbent assay, a radioimmunoassay, an immunofluorescence assay, or a Western blot.

17. The diagnostic kit of claim 16 further comprising reagents for performing said method selected from colorimetric agents, ELISA blocking reagents, positive and negative controls, or wash buffers.

18. The diagnostic kit of claim 12, wherein said substrate is a gel.

19. The diagnostic kit of claim 12, wherein said substrate is a Western blot membrane.

20. The diagnostic kit of claim 19, wherein said Western blot membrane comprises a polyvinylidene fluoride material.

21. The diagnostic kit of claim 12 further comprising at least one microtiter plate.

22. A pharmaceutical composition comprising at least one purified ligand of jbefa II spectrin protein or a fragment thereof; and a pharmaceutically acceptable buffer, solvent, diluent, adjuvant, or carrier.

23. A method of treating or delaying the pathological effects of primary and secondary Sjogren's Syndrome in a patient comprising administering a therapeutic or prophylactic amount of a pharmaceutical composition to said patient comprising at least one purified ligand of beta II spectrin protein or a fragment thereof in association with a pharmaceutically acceptable carrier.

24. The method of claim 23, wherein said patient is a human.

25. The method of claim 23, wherein said administration of said pharmaceutical composition is parenteral, topical, or a combination thereof.