Responsiveness of germfree mice in mixed leukocyte culture. Reexamining the nature of the responding unit.

Conventional (cv) and germfree (gf) mice are able to give a good proliferative response to allogeneic cells in the mixed leukocyte culture (MLC) test, while the response to xenogeneic stimulating cells has been in question. Previous studies by others have suggested only a low MLC response in cv animals and none in gf ones. We have found that both cv and gf animals can give a good MLC response to xenogeneic as well as allogeneic cells. These findings are of importance for our understanding of both MLC stimulation and response.