The immunosuppressive effect of monoclonal anti‐Lyt‐1.1 antibodies in vivo

Abstract

Monoclonal anti‐Lyt‐1.1 alloantibody was produced as tissue culture supernatant and administered to mice. The antibody, given intraperitoneally, resulted in the suppression of all T cell functions studied, but was without direct effect on B cells. Thus, skin and tumor allograft survival was prolonged and there was suppression of the delayed‐type hypersensitivity response; T cell help in the anti‐sheep red blood cell antibody response, responder cells in the mixed lymphocyte reaction (MLR), leucoagglutinin‐responsive cells, cytotoxic T cell (T_c) function and the induction of T_c were either totally or partially suppressed, all these responses being mediated by Lyt‐1⁺2⁻ or Lyt‐1⁺2⁺ cells in CBA/H mice. By contrast, there was no inhibitory effect on the MLR‐stimulating or lipopolysaccharide‐responsive cells. The administration of the anti‐Lyt‐1.1 antibody was accompanied by a depletion of Lyt‐1.1⁺ T cells from both spleen and lymph node. These studies indicate that the monoclonal anti‐Lyt‐1.1 antibody is active in vivo with a selective effect on T cells. The results also have important implications for studies of T cell interactions in the mouse in vivo, and for similar studies in man.