Major histocompatibility complex (B): effect on the response of chickens to a second challenge with rous sarcoma virus.

The influence of B genotype on the formation of a second RSV-induced tumor was studied. Line 6(3) (B2/B2) and (6(1) x 15(1))F3 and F4 B2/B2 and B5/B5 chickens were challenged with RSV in the left wingweb at 6 weeks of age. Tumor-bearing animals then were rechallenged with RSV in the right wingweb at either 10, 11, or 12 days post primary inoculation. Most B2/B2 hosts resisted development of a second tumor compared to none of the B5/B5 hosts. Failure of a second tumor to develop in B2/B2 hosts was not explained by humoral neutralization of RSV in vivo, since sera from 83% of B2/B2 and 100% of B5/B5 tumor bearing chickens failed to neutralize virus prior to 12 days post primary inoculation. Humoral antiviral immunity appeared later in B5/B5 than in B2/B2 hosts. Humoral antiviral immunity appears to play little if any role in resistance to early RSV-induced tumor development, but likely both humoral and cell-mediated antitumor immunity do.