Staph Superantigen Induces Lupus-Like Features in Mice

Mice study shows chronic exposure to SAg triggers systemic inflammatory disease similar to SLE

MONDAY, Aug. 13 (HealthDay News) -- Chronic exposure to superantigen (SAg)-producing Staphylococcus aureus can induce systemic inflammatory disease symptoms in mice, with features similar to those of systemic lupus erythematosus (SLE), according to a study published online July 13 in The Journal of Immunology.

To examine whether chronic exposure to small amounts of SAg could activate autoreactive CD4+ and CD8+ T cells and precipitate autoimmune disease, Vaidehi R. Chowdhary, M.D., from the Mayo Clinic in Rochester, Minn., and colleagues implanted HLA-DQ8 transgenic mice subcutaneously with mini-osmotic pumps that were able to continuously deliver the SAg, staphylococcal enterotoxin B (10 µg per mouse) or phosphate-buffered saline.

The researchers found that, following chronic exposure to staphylococcal enterotoxin B, the mice displayed symptoms of a multisystem autoimmune inflammatory disease with similar features to SLE, which was characterized by mononuclear cell infiltration of the lungs, liver, and kidney. This was accompanied by anti-nuclear antibody production and deposition of immune complexes in the renal glomeruli. The infiltrates were predominantly comprised of CD4+ T cells bearing T cell receptor Vβ8. In mice lacking CD4+ T cells and CD28, there was a marked reduction in the extent of immunopathology.

"Our study suggests that Staphylococcus aureus carriage might play a role in the pathogenesis of lupus or other autoimmune diseases and that several host and bacterial determinants might shape the final outcome," the authors conclude.

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