The activation of guinea pig T lymphocytes by anti-beta 2-microglobulin serum.

In order to study further the role of beta 2-m in the regulation of the immune response, we have examined the effects of a goat anti-guinea pig beta 2-m serum on a number of T lymphocyte functions in vitro. Anti-beta 2-m serum produced a marked inhibition of the response of peritoneal exudate T cells to antigen and mitogen stimulation. Surprisingly, a marked activation of lymph node T lymphocyte proliferation was observed in the absence of antigen or mitogen stimulation. This stimulatory effect of anti-beta 2-m serum was shown to be specific for beta 2-m and required the presence of macrophages. The T cell proliferative response induced by anti-beta 2-m could not be blocked by antisera to the antigens of the guinea pig MHC. These studies suggest that beta2-m may play some critical role in the immune response at the level of T cell activation.