Marek's disease tumor-associated surface antigen (MATSA) in resistant versus susceptible chickens.

The appearance of MATSA-bearing cells in the spleens of genetically susceptible (P-line) and resistant (N-line) chickens followed similar patterns at 4 and 6 days postinoculation (PI), with 4 to 10% of the cells positive in indirect fluorescent-antibody tests. Levels of MATSA-positive cells at 10, 14, and 21 days PI continued at 6-8% in P-line birds but dropped from about 8% to below 1 or 2% in N-line birds. This pattern was seen also in virus-isolation rates from the same spleen samples. Viral internal antigens (VIA) were seen equally and with decreasing incidence in both groups at 4-10 days PI. VIA were not detected at 14 days but reappeared at 21 days, with higher levels in P-lines than inN-lines. It was concluded that genetic resistance to Marek's disease is not related to events which result in production of the putative tumor antigen, MATSA, but rather to host-controlled factors which terminate those events.