Cellular Recognition by Mouse Lymphocytes in Vitro

Abstract

The in vitro stimulation of mouse spleen cells by foreign histocompatibility antigens is described. Spleen cells from mice less than 3 weeks of age could not be stimulated in mixed lymphocyte cultures. They were also deficient in their ability to stimulate adult allogeneic cells in mixed lymphocyte cultures. The ability of the cells to be stimulated by histocompatibility antigens was correlated in time with their ability to stimulate allogeneic cells. Stimulation of mouse spleen cells was accomplished by allogeneic spleen cells with differences at the H-2 locus or at the H-3, H-13 loci, and with soluble H-2 antigen. F₁ hybrid spleen cells were stimulated by parental strain spleen cells or by parental strain red blood cell stroma. Immunization with allogeneic spleen cells was found to transiently affect the degree of stimulation obtained in mixed lymphocyte cultures of spleen cells from the immunized mice mixed with mitomycin-treated cells of the strain used for immunization. The cells from immunized animals also showed an increased degree of stimulation when reacted in MLC with allogeneic cells sharing some of the H-2 antigens of the strain used for the immunization. Immunization did not affect the degree of stimulation obtained in MLC of cells from strains with weak histocompatibility differences. The possible explanations of in vitro lymphocyte stimulation by histocompatibility antigens of allogeneic or semi-allogeneic cells are discussed.