Factors involved in the expression of cowpox virus-specific antigen in Sendai virus carrier cells.

Formation of cowpox virus-specific cell surface antigen (CPVS-ag) HVJ (Sendai virus) carrier cells compared to that in parent cells. Temperature shifts from 32 to 35 to 37 degrees C for these carrier cultures reduced this enhancing activity, making them equivalent to parent cells. The eclips phase and one-step growth of CPV in the carrier cells were shorter than in normal cells. Extracts of carrier cells exhibited a stimulating activity causing the temporary rise and subsequent lowering of CPV infectivity in their reactions with CPV in vitro, suggesting a cellular acceleration of CPV uncoating. The S-ag forming ability of these carrier cells did not decrease as much as that of parent cellsin the presence of actinomycin D or puromycin. The results indicate that persistent infection with HVJ, especially the temperature-sensitive variant, promotes the first step of intracellular growth of CPV, resulting in enhanced formation of S-ag.