Tests of association of lymphocyte alloantigen genotypes with resistance to viral oncogenesis in chickens. 2. Rous sarcoma and lymphoid leukosis in progeny derived from 6(3) X 15(1) and 100 X 6(3) crosses.

Chickens from inbred line RPRL 6(3) are resistant to virally-induced Marek's disease (MD) and lymphoid leukosis (LL) and are relatively strong regressors of virally induced Rous sarcomas. Line 6(3) chickens are homozygous for three independent loci determining surface alloantigens of lymphocytes, Th-1 and Ly-4 on thymus-derived (T) cells and Bu-1 on bursa-derived (B) cells. In contrast, RPRL Lines 100 and 15(1) are highly susceptible to MD and LL and are weaker regressors of Rous sarcomas than 6(3). RPRL Lines 100 and 15(1) are homozygous for different alleles at the Th-1 and Ly-4 loci than 6(3), whereas only Line 100 differs from 6(3) at Bu-1. To test the possible association of these three antigen loci with variations in resistance to virally-induced tumors, homozygous genotypes among later generations derived from 6(3) X 15(1) and 100 X 6(3) crosses were identified by means of immunofluorescence testing of peripheral blood lymphocytes. Test progeny were then bred from matings of homozygous parents. No association was found between Rous sarcoma regression and the Th-1 and Ly-4 T cell alloantigen loci in F6 (6(3) X 15(1)) chickens, but the Bu-1 locus influenced rate of regression in F3 (100 X 6(3)) chickens. The Ly-4 in F6 (6(3) X 15(1)) and Bu-1 in the F3 (100 X 6(3)) chickens did not influence the incidence of LL. However, Th-1 influenced LL in F3 (100 X 6(3)) chickens (P less than .05) and possibly influenced LL in F6 (6(3) X 15(1)) chickens (P less than .09).