Effect of anti-T cell autoantibodies from systemic lupus erythematosus sera upon T lymphocyte functions

This study was undertaken to establish whether IgM and IgG anti-T cell autoantibodies obtained from sera of patients with active systemic lupus erythematosus, impair normal T lymphocyte functions. Two in vitro models of T cell function were examined: (a) the capacity of cells to cap, endocytose, and regenerate the T3, T4, and T8 surface antigens; and (b) the adenosine-induced T4----T8 phenotype switch. The results demonstrated that autoantibody neither impaired the capping process, nor impeded the phenotypic switch. Thus, bound anti-T cell autoantibodies do not appear to interfere with these specific T lymphocyte functions and cannot directly account for either the impaired T cell capping mechanism or the block in adenosine-induced phenotype switch observed during active systemic lupus erythematosus.