Genetic interaction between non-MHC T- and B-cell alloantigens in response to Rous sarcomas in chickens

Area of Science:

• Immunogenetics
• Avian tumor virology
• Poultry genetics

Background:

• Chickens from Regional Poultry Research Laboratory (RPRL) inbred lines 6(3) and 100 exhibit differential regression of Rous sarcoma virus-induced tumors.
• These lines are genetically identical at the major histocompatibility B complex but differ at three autosomal loci: Ly-4, Th-1, and Bu-1.
• These loci control surface alloantigens on T and B lymphocytes, respectively.

Purpose of the Study:

• To investigate the association between genotypes at the Ly-4, Th-1, and Bu-1 loci and the quantitative variation in Rous sarcoma regression.
• To determine the role of these specific genetic loci in the immune response against viral-induced tumors in chickens.

Main Methods:

• Analysis of segregating F4 generation progeny derived from crosses between RPRL lines 100 and 6(3).
• Genotyping of progeny at the Ly-4, Th-1, and Bu-1 loci.
• Quantification of Rous sarcoma tumor regression ability in relation to specific genotypes.

Main Results:

• Genotypes at the Ly-4 and Bu-1 loci were significantly associated with Rous sarcoma regression.
• The Th-1 genotype did not show a significant association with tumor regression.
• Chickens with Ly-4a/Ly-4a, Bu-1b/Bu-1b and Ly-4b/Ly-4b, Bu-1a/Bu-1a genotypes displayed significantly higher tumor regression ability compared to other double homozygous genotypes.

Conclusions:

• Tumor regression is influenced by the interaction between the Ly-4 and Bu-1 gene loci.
• Complementation between specific alleles at the Ly-4 and Bu-1 loci (line 6 Ly-4a with line 100 Bu-1b, or line 100 Ly-4b with line 6 Bu-1a) enhances regression ability.
• These findings highlight the importance of specific autosomal gene interactions in mediating anti-tumor immunity in chickens.