Influence of different B-complex recombinants on the outcome of Rous sarcomas in chickens.

Seven major histocompatibility (B) complex recombinants were evaluated for anti-Rous sarcoma response. In experiment 1, the BR5(F21-G19) recombinant haplotype both homozygous and in heterozygous combinations with B19 and B21 haplotypes were compared to B19/B19 and B21/B21 chickens to determine the relative influence of the BF versus BG chromosomal segments on regression of Rous sarcoma virus-induced tumours. In experiment 2, six recombinant haplotypes BR1(F24-G23), BR2(F2-G23), BR3(F2-G23), BR4(F2-G23), BR6(F21-G23) and BR8(F2-G2a,23) present in chickens heterozygous for normal haplotypes B19, B23 or B26 were compared for anti-sarcoma response. A total of 1328 chickens were blood typed for B alloantigens at 17 days of age, inoculated in the wingweb with Rous sarcoma virus at 6 weeks and monitored for anti-tumour immune response over a 10-week period. Genotypes which shared the same BF haplotype, but differed in their BG regions, had similar anti-tumour responses, implicating the BF but not the BG region in tumour regression. Chickens carrying BF2 or BF21 had a strong anti-tumour response, while BF24 conferred a weaker response, regardless of the accompanying normal haplotype.