Immunological interaction between allogeneic and xenogeneic rodent spleen cells in culture: stimulation of DNA synthesis.

An early proliferative response measured by [H] thymidine uptake occurred following mixing and culture of spleen cell suspensions derived from genetically unrelated rodents. This response reached a maximum value at 40–44 hr. When either component of the mixture in equivalent amounts was cultured alone, only a limited response occurred. This marked stimulation of DNA synthesis occurred when spleen cells derived from LAF mice and a pool of spleen cells from three non-inbred rats were mixed and cultured. No such response occurred in the mouse spleen cultures either in the absence of rat spleen cells, or in the presence of disrupted rat spleen cells. An equally marked response occurred when spleen cells from one rat were mixed and cultured either with C57BL10J or DBA/2J mouse spleen cells, or to a lesser extent with spleen cells from a second unrelated non-inbred rat. A similar marked response occurred with cells derived from C57BL10J and DBA/2J and from BALB/c and C3H/HeJ mice. The existing data suggest that the response of these rodent spleen cells in the mixed lymphocyte culture (MLC) test is dependent on certain genetic differences inherent in the two cell populations.