Characterization of autoantibodies directed against T cell receptors.

Recently it has been observed that administration of intravenous immunoglobulin (IVIG) can have profound effects on a wide variety of diseases related to the dysregulation of the immune system. The mechanisms which explain these activities are poorly understood. Human IVIG and various Cohn plasma fractions contain autoantibodies directed against T cell receptors (Tcr). Previous studies have shown that IVIG contains autoantibodies against T cell receptor peptides. In order to further our understanding of autoantibody specificities, a single chain Tcr (scTcr) was constructed by recombinant DNA techniques from the variable alpha and variable beta chains of the Jurkat cell line. Anti-Tcr autoantibodies were isolated from IVIG and Cohn fractions I + III using a scTcr affinity column. This scTcr affinity purified material reacted with the surfaces of T cells at 10 micrograms/ml whereas non-purified IVIG did not. Sera from patients with rheumatoid arthritis (RA) as well as serum from patients with systemic lupus erythematosus (SLE) reacted with the scTcr at levels above that of normals.