Technical Data
The La/SS-B antigen is a 47kD ribonucleic protein that is associated with a spectrum of small RNAs. La/SS-B appears to be readily susceptible to proteolysis, resulting in many smaller (42, 320, and 270kD) but still immunoreactive polypeptides. 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. Anti-La/SS-B autoantibodies were described originally as precipitating autoantibodies in sera of Sjogren's Syndrome patients and referred to as SjT. 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. Autoantibodies against La/SS-B are also commonly found in Systemic Lupus Erythematosus and Subacute Cutaneous Lupus. 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.

Suitable for use in ELISA, Immunodiffusion and Immunoprecipitation. Other applications not tested.

Recommended Dilutions:
ELISA: 1:100
Optimal dilutions to be determined by the researcher.

Immunodiffusion: 1:8

Anti-La/SS-B Activity by ELISA: As Reported (lot-specific).

In an ELISA system designed to detect all IgG subclasses, the following purified antigens (dilution of 1:100) responded as:
Antigen Result (EU/ml)
SSA 102
SSB 148
Sm 0
Sm/RNP 62
Jo-1 2

Interpretation of Results:
<16 EU/ml: Negative
16-20 EU/ml: Equivocal
>20 EU/ml: Positive

Storage and Stability:
Lyophilized powder may be stored at -20C. Stable for 12 months after receipt at -20C. Reconstitute with sterile ddH2O. Aliquot to avoid repeated freezing and thawing. Store at -20C. Reconstituted product is stable for 12 months at -20C. 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.
2ml-20CBlue IceHumanHuman
Not Determined
Purified from donor human serum.
Purified by fractionation of delipidated and defibrinated donor human serum.
Supplied as a lyophilized powder from PBS, 0.02% sodium azide. Reconstitute with 2ml sterile ddH2O.
Recognizes human La/SS-B. Specificity is verified by a precipitin line of identity with the CDC-AF reference serum. Crossreactivity: SSA. No reactivity at a dilution of 1:100 when tested against purified Scl-70, Sm, Sm/RNP and Jo-1 antigens in an ELISA system designed to detect all IgG subclasses.
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.
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).