The Role of Thymus-Derived Lymphocytes in the in Vitro Activation of Macrophages to Kill Listeria Monocytogenes

Abstract

When sensitized spleen cells from guinea pigs chronically infected with Toxoplasma gondii were cultured with normal guinea pig peritoneal macrophages in the presence and absence of Toxoplasma antigen, macrophage monolayers incubated with sensitized spleen cells and antigen were markedly resistant to challenge with Listeria monocytogenes. Experiments were performed to determine the role of thymus-derived lymphocytes in the in vitro activation of macrophages by pretreating the sensitized spleen cells with an antiserum (ATS) prepared in rabbits against fetal guinea pig thymus cells. In the presence of complement, treatment of sensitized spleen cells with ATS completely abolished their ability to activate normal macrophages in the presence of antigen.