Genetic control of allogeneic interactions in the guinea-pig. V. Evidence for a dissociation between genes coding for A GPLA-B region-controlled determinant and genes coding for MLC suppressor cells.

The genetic basis of guinea-pig leucocyte antigen (GPLA)-B.2-associated unresponsiveness in the guinea-pig mixed leucocyte culture (MLC) was investigated using fibroblasts as stimulating cells. Guinea-pig foetal fibroblasts bearing the B.2 specificity can stimulate allogeneic but not syngeneic lymph node lymphocytes, whereas B.2-bearing peritoneal exudate cells (PEC) induce specific unresponsiveness. The inhibition of the mixed leucocyte-fibroblast reaction is seen only when the alloantisera are directed against the stimulatory fibroblast rather than the responding lymph node lymphocytes. Furthermore, B.2-bearing fibroblasts, in contrast to B.2-bearing PEC, fail to elaborate MLC-suppressor factor. It appears therefore, that in guinea-pig fibroblasts there is an apparent dissociation between major histocompatibility complex (MHC; in the region of the B locus) genes and the gene(s) coding for B.2-associated MLC suppressor cells and factor(s).