Submitted to: Immunogenetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/23/1996
Publication Date: N/A
Interpretive Summary: In chickens, as in most higher vertebrates, one group of genes that vary between individuals is known to determine rapid rejection of foreign tissues, e.g., skin grafts. The genes in this major histocompatibility complex (MHC or B complex) define antigens that result in immune rejection. These same MHC genes are important in immune defense against disease causing organisms. If tissues are exchanged between animals that are identical for major genes then a slower rejection of tissues occurs due to genetic differences attributable to minor histocompatibility genes. In chickens, a second group of MHC type genes (the Y complex) that is inherited independently of the B MHC has recently been defined. In this study, we show that genetic differences in the Y complex also influence the frequency and time of rejection of skin grafts. This suggests Y genes in the chicken may be important for disease resistance. The importance of this ancillary Y complex on skin graft rejection in chickens suggest that ancillary MHC genes in other species may also be critical in tissue transplantation.
Technical Abstract: Major histocompatibility complex (Mhc) genes influencing transplantation rejections were first described in mice within the H-2 complex, and secondly in chickens within the B complex. In chickens a second Mhc complex termed Rfp-Y has recently been identified which contains classical class I and class II genes that assort independently from the B complex. Three Rfp-Y haplotypes have been defined in a closed breeding flock of line N chickens. In this study progeny were obtained from line N Rfp-Y heterozygous matings to establish the role of Rfp-Y on transplantation immunity. Rfp-Y incompatibility did not induce significant one-way mixed lymphocyte responses. However, Rfp-Y incompatible skin grafts were rejected more frequently and at a faster rate by 2-week-old chicks than were Rfp-Y compatible grafts. These data suggest that molecules from the Rfp-Y haplotype determine histocompatible antigens. The Rfp-Y haplotype influence on transplantation in chickens may be relevant to humans and other species where polymorphic classical Mhc genes have been defined that segregate independently from well-defined Mhc haplotypes.