Characterization of Lithium Effects on Two Aspects of T-Cell Function

There is increasing evidence that positive and negative feedback control mechanisms regulate the immune response. At the molecular level, candidates for these regulatory effects are the cyclic nucleotides. Although most of the studies demonstrating a role for these compounds have involved non-lymphoid tissues, cyclic nucleotides also appear to be important mediators in the regulation of a variety of specific lymphocyte functions. These functions include triggering of differentiation, expression of discrete receptor activities, lymphocyte proliferation, cytotoxicity, antibody production and the release of lymphokines (Strom et al., 1977). We have examined the role of drugs known to involve cyclic nucleotide synthesis or degradation, in modulating the expression of different lymphocyte responses, and have investigated the potential of lithium as a putative blocker of membrane adenylate cyclase, to counter these effects. In this paper we will describe our studies of lithium effects on two aspects of T-cell function, namely the ability to express the receptor for sheep red blood cells (SRBC) and the prolif erative response to a number of mitogens. In the accompanying paper, the effect of lithium on the expression of suppressor cell activity in vitro and in vivo will be discussed.