Adult murine T cells activated in vitro by alpha-fetoprotein and naturally occurring T cells in newborn mice: identity in function and cell surface differentiation antigens.

Abstract

Murine .alpha.-fetoprotein (.alpha.FP) suppresses T [thymus-derived] cell-dependent antibody responses in vitro but not T cell-independent responses. Earlier preliminary findings indicated that such inhibitory effects were mediated via activated T cells. .alpha.FP was used as the inducing agent to analyze cells generated in vitro from adult spleen cells with regard to function and surface markers. The cells were then compared to the naturally occurring splenic T cells of newborn mice, in which there are high intrinsic concentrations of .alpha.FP. Both types of T lymphocytes effectively inhibited T cell-dependent antibody responses in vitro but not T cell-independent responses. Moreover, both groups of T cells expressed the identical differentiation antigen phenotype, Ly 1+2-. Thus .alpha.FP-induced inhibitory T cells from adults had the same functional properties and Ly phenotype as splenic T lymphocytes from newborn mice. These findings support the concept that .alpha.FP might function as an important immunoregulatory agent in vivo during ontogenetic development.