Response of six major histocompatibility (B) complex recombinant haplotypes to Rous sarcomas

Area of Science:

• Immunogenetics
• Avian viral oncology
• Chicken disease resistance

Background:

• The B complex in chickens plays a crucial role in immune responses, including resistance to viral diseases.
• Rous sarcoma virus (RSV) induces tumors in chickens, making it a model for studying tumor regression and genetic control of disease resistance.

Purpose of the Study:

• To investigate the impact of specific B complex recombinants on Rous sarcoma tumor regression.
• To identify genetic factors within the B complex that influence the ability of chickens to regress tumors induced by RSV.

Main Methods:

• Generation of six B complex recombinants (BR1-BR6) through backcrossing to the UCD 003 (B17B17) inbred line.
• Wingweb inoculation of chicks with Rous sarcoma virus (RSV) at six weeks of age.
• Evaluation of tumor regression using a tumor profile index (TPI) analyzed by variance.

Main Results:

• Significant differences in TPI were observed among various homozygous and heterozygous B complex genotypes.
• BR2BR2, BR3BR3, and BR4BR4 (F2-G23 recombinants) showed differential tumor regression, despite serological similarity.
• BR6BR6 (F21-G23) exhibited significantly lower TPI compared to most other homozygotes, suggesting unique genetic influences.

Conclusions:

• Serologically similar B complex recombinants can harbor distinct genes that affect tumor regression.
• Genetic variations within the B-F/B-L or B-G regions may account for differing tumor regression capabilities observed in recombinants like BR5 and BR6.