Immunofluorescence of abortive and complete infections by influenza A virus in hamster BHK21 cells and mouse L cells.

The synthesis and transport of the soluble antigen of influenza A virus were traced by immunofluorescent staining with human convalescent sera during abortive and complete infection of hamster BHK21 ceils and mouse L ceils. Times of synthesis in the nucleus, transport to the cytoplasm and extrusion by the cell were the same in complete and in abortive infection. The product of abortive infection contained soluble antigen, went through the same stages of adsorption, penetration and disposal as infectious virus but differed from it in being non-infectious, non-interfering and in not producing phenotypic mixing. These deficiencies suggest that RNA is either absent from or fails to function in abortive virus. Ring-like structures were detected in the nucleus at late stages in the synthetic cycle. Their antigenic nature was not ascertained but in L cells soluble antigen appeared first round a nucleolar halo.