MHC CLASS II-MEDIATED T-CELL RESPONSE TO DNA

Anti-DNA antibodies are elevated in several autoimmune diseases, inclu ding systemic lupus erythematosus, Yet, DNA was not shown to be presen ted by molecules of the major histocompatibility complex (MHC), nor wa s it reported to specifically stimulate T cells in vivo, although thes e steps are essential for antibody production. We now demonstrate DNA- specific T cell activation, which involves presentation of DNA by MHC class II molecules. T cells, isolated from lymph nodes of mice immuniz ed with a murine monoclonal anti-anti-DNA antibody, proliferated in re sponse to DNA. Moreover, presentation of DNA by murine antigen-present ing cells could be inhibited with an isotype-specific anti-Ia antibody , and with peptides restricted by the same H-2 haplotype, suggesting t hat it is MHC class II-mediated. These results indicate that DNA can p lay a direct role in the regulation of T cells and in autoimmune proce sses. (C) 1996 Academic Press, Inc.