Reconstitution of the Antibody Response in Vitro of T Cell-Deprived Spleen Cells by Supernatants from Spleen Cell Cultures

Abstract

Abstract The antibody response of spleen cells against sheep red cells was tested in vitro with the Mishell-Dutton technique. Spleen cells deprived of thymus-derived (T) cells by anti-θ serum treatment gave a low response. Supernatants from cultures of either parental or syngeneic spleen cells could restore the response of T cell-deprived spleen cells against sheep red cells to a certain degree, but supernatants from mixed lymphocyte cultures between two H-2 incompatible parental strains were more efficient in this respect. These supernatants also could stimulate markedly the immune response of spleen cells from athymic “nude” mice. Addition of supernatants to cultures of normal or T cell-depleted cells caused an early appearance of plaque-forming cells by day 2 with a maximal number on day 3 for the T cell-depleted cells. Supernatants harvested on day 1 were more effective than supernatants from day 2 in restoring the immune response, whereas supernatants from days 3 and 4 were inhibitory. This was not due to an excessive production of the restorative factor. Both T cells and adherent cells were necessary for the production of the restorative factor. The active factor in the supernatants could be produced in serum-free medium and was capable of supporting a primary antibody response of spleen cells cultured in normal mouse serum. The findings suggest that T cells may stimulate the antibody response of bone marrow-derived cells by means of a soluble factor.