ABSTRACT
Lipopolysaccharide (LPS) endotoxin has a variety of biological effects on numerous types of mammalian cells, including immunocompetent cells. Therefore, the results suggested that the stimulatory effect of LPS to C3H/He splenic T cells might depend on its endotoxic activity the antigenicity. The synergistic effect on thymic T cells was dependent on la-positive accessory cells such as macrophages and was mainly due to the action of the enhanced production of IL-2, which was released by the T cells in response to concanavalin A and LPS. T cells are necessary to induce the effect of LPS on the antibody response to TD antigen. Although evidence for the direct action of LPS or lipid A on T cells is obscure, LPS can support the proliferative response of T cells stimulation with antigenvia mediators produced by LPS-stimulated macrophages. Although direct activation of cytotoxic CD8T cells by LPS is known, IL-12 derived from LPS-activated macrophages augment the cytotoxic effect of CD8T cells and NK cells.
