La/SS-B Antigen, Calf Thymus

The La/SS-B antigen is a 47kD ribonucleic protein that is associated with a spectrum of small RNAs (2). La/SS-B appears to be readily susceptible to proteolysis, resulting in many smaller (42, 320, and 270kD) but still immunoreactive polypeptides (3). It has been shown that the La/SS-B antigen primarily resides in the nucleus (2). It appears to be associated with RNA polymerase III transcripts (4). It has also been shown that the La/SS-B antigen shows strong conservation across species (5). Anti-La/SS-B autoantibodies were described originally as precipitating autoantibodies in sera of Sjogren's Syndrome patients and referred to as SjT.(1) A precipitin with the same properties was rediscovered later and termed La and then SS-B. Anti-La/SS-B precipitins.The presence of autoantibodies against the La/SS-B antigen has been advocated as a diagnostic aid in Sjogren's Syndrome patients (6). Autoantibodies against La/SS-B are also commonly found in Systemic Lupus Erythematosus and Subacute Cutaneous Lupus (4). In addition, there appears to be a correlation between anti-La/SS-B and the absence of nephritis in SLE patients. Studies have demonstrated that SLE patients with precipitating Anti-Ro/SS-A antibodies have a high incidence of serious nephritis (53%), while those with both Anti-Ro/SS-A and Anti-La/SS-B have a low (9%) frequency of nephritis (7). \n\nApplications:\nSuitable for use in Immunodiffusion. Other applications not tested.\n\nRecommended Dilutions:\nSome assay systems may require more concentrated or more diluted extract. Optimal dilutions to be determined by researcher.\n\nStorage and Stability: Lyophilized powder may be stored at 4 degrees C for short-term only. Reconstitute to nominal volume by adding sterile dH2O, aliquot and store at -20 degrees C. Reconstituted product is stable for 12 months at \n-20 degrees C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.

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SPECIFICATIONS

Catalog Number

L1380-05

Size

5mg

Applications

ELISA, WB

Form

Supplied as a lyophilized powder in PBS, 0.02% sodium azide.\nReconstitution: Reconstitute with 1ml dH2O. Note: Some precipitate may occur. Will not affect product performance.

Purity

Purified by a combination of protein fractionation and column chromatography.\nContaminants: Most contaminating antigens have been removed by immunoadsorbent methodology.

References

1. Harley, J.B., Yamagata, H., Reichlin, M.: Anti-La/SS-B antibody is present in some normal sera and is coincident with anti-Ro/SSA precipitins in systemic lupus erythematosus. J. Rheum. 11: 309-314 (1984). 2. Bachman, M., Mayet, W.J., Shroder, H.C., et al.: Association of La and Ro antigens with intracellular structures in HEp-2 carcinoma Cells. Cell Biology 83: 7770-7774 (1986). 3. Habets, W.J., den Brok, J.H., AM Th.,Boerbooms, van de Putte, L.B.A., van Venrooij, W.J.: Characterization of SS-B (La) antigen in adenovirus-infected and uninfected HeLa cells. EMBO J. pp1625 (1983). 4. Harley, J.B., Rosario, M.O., Yamagata, H., et al.: Immunologic and Structural Studies of the Lupus/Sjogren's Syndrome Autoantigen, La/SSB, with a Monoclonal Antibody: 76: 801-806 (1985). 5. Hoch, S.O., Billings, P.B. (Agouron Institute): Characterization of the La (SS-B) Antigen From Several Mammalian Sources. J. of Immun. 133: 1397-1403 (1984). 6. Harley, J.B., Alexander, E.L., Bias, W.B., Fox, O.F., et al.: Anti-Ro/SSA and Anti-La/SSB in Sjogren's syndrome. Dept of Med, Okla Med Research Foundation. pg 1-35. 7. Reichlin, M.: Clinical and Immunological Significance of Antibodies to Ro and La in Systemic Lupus Erythematosus. Arthritis and Rheumatism 25: 767-772 (1982). 8. Harley, J.B., Yamagata, H., Reichlin, M.: Anti-La/SSB Antibody is Present in Some Normal Sera and is Coincident with Anti-Ro/SSA Precipitins in Systemic Lupus Erythematosus. J. of Rheumatology pg 309-314 (1984).

Additional Info

Activity: Reacts with La/SS-B antisera in immunodiffusion. No reaction is observed with antisera to nRNP, Ro/ SS-A, Sm, Scl-70, or Jo-1 in immunodiffusion. The activity of this product will vary with the assay conditions.