Monoclonal anti-Lyt-1 (αLyt-1) and αLyt-2 manifest inverse effects on allogeneic mixed lymphocyte reactions when added to the reaction mixtures without complement. αLyt-1 augments cell proliferation and generation of cytotoxic cells but has no effect on cell-mediated cytolysis, whereas αLyt-2 blocks cell proliferation, generation of killer cells, and cytolytic activity of killer cells. The augmenting effect of αLyt-1 cannot be attributed to a direct mitogenic effect on T cells. Both inhibition by αLyt-2 and potentiation by αLyt-1 require interaction of responder cells with the antibodies during the first 24 hr of the mixed lymphocyte reaction, indicating that early stages of the reaction are sensitive to Lyt antibodies. The enhancing effect of αLyt-1 on alloantigen-induced T-cell proliferation is associated with augmented production of T-cell growth factors. When αLyt-1 is present in mixed lymphocyte cultures, the supernatant media collected after 24 or 48 hr of culture induce higher proliferation of activated T cells compared to media of mixed lymphocyte cultures incubated in the absence of antibodies or in the presence of αLyt-2 which has no effect on secretion of growth factors. The differences in the effects of αLyt-1 and αLyt-2 could not be attributed to differences in heavy chain constant region functions because both were of the same γ(2A) immunoglobulin class and were used at the same concentration. The data suggest a possible role for Lyt-1 molecules in early activation and mitogenesis processes such as production of growth factors.
|Number of pages||4|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Issue number||2 II|
|State||Published - 1981|