Identification of haplotypes of the chicken major histocompatibility complex (B).

Abstract

The chromosomal region presently known to contain the major histocompatibility complex of the chicken was first detected in 1947 using alloimmune hemagglutinating reagents and was tentatively assigned the locus symbol D in studies on the time of development of cellular antigens (Briles et al. 1948) and on its role in inducing hemolytic disease among chicks from alloimmunized hens (Briles 1948). The locus symbol was subsequently changed to B to symbolize the second chicken blood group system discovered at the University of Wisconsin (Briles et al. 1950). One of two blood group loci discovered independently by Gilmour (1959) was shown by an exchange of antisera to correspond to the Wisconsin B system. The early recognition that blood group systems were characterized by extensive polymorphism within rather narrowly based genetic stocks of chickens (Briles et al. 1957, Gilmour 1959) placed emphasis on investigating their possible effects on fitness and survival within populations or experimental crosses. As a result of this emphasis on within-laboratory studies, there was little sustained interest during the 1950-1970 period in the development of a broadly applicable system of uniform haplotype terminology. The discovery of histocompatibility-linked immune response genes in mammals (Benacerraf and McDevitt 1972) and the subsequent demonstration of immune response (Giinther et al. 1974, Benedict et al. 1975) and disease resistance (Hansen et al. 1967, Briles and Oleson 1971) associated with particular alleles at the B locus in the chicken created a need for information regarding possible haplotype homologies between genetic stocks being studied in separate laboratories. The technique for detecting possible homologies between lines was utilized from the beginning of the work at Texas A and M University (Briles 1952, Briles et al. 1957) and, soon after establishing work on a diverse group of mildly inbred lines at the DeKalb AgResearch Laboratory in early 1958, a common haplotype terminology across lines was developed and later published in part to illustrate frequency profiles in inbred parent lines of chickens (Briles 1972). More recently, as a consequence of reagent preparation in a genetically diverse chicken colony at Northern Illinois University combined with the typing of