The mixed leukocyte reaction in chickens. Evidence for control by the major histocompatibility complex

Abstract

One‐way and two‐way mixed leukocyte reactions (MLR) have been performed using cells isolated from peripheral blood of chickens from four different inbred lines (CA, CB, WA and WB).MLR between chickens from the same line, or from lines CA and CB (which have the same major histocompatibility antigens (B antigens)) were always negative; MLR between chickens from lines differing at the B locus were always positive, even when the lines compared (WA, WB) had otherwise identical or very similar genetic backgrounds. This evidence that a locus or loci controlling the MLR is linked to the major histocompatibility locus in the chicken was confirmed by the results of MLR performed with leukocytes from the F2 progeny of a WA × CB cross. These experiments also exclude (at least for the WA/CB combination) the role in the reaction of other, non‐B‐linked MLR loci.The evolution of the vertebrate major histocompatibility complex is discussed in the light of these findings.