Genetic expression of human adenoviruses in simian cells. Evidence for interserotypic inhibition of viral DNA synthesis.

Most simian cells are permissive for SV40 and adenovirus-SV40 hybrids but nonpermissive for human adenoviruses, and the defect has been shown to take place at the level of processing of late viral mRNAs (Klessig and Grodzicker, 1979). Viral DNA synthesis and virus progeny production were studied in simian cells infected with different adenovirus serotypes. Adenoviruses belonging to oncogenic subgroups A and B (Ad31 and Ad3) failed to replicate their DNA in CV1 cells, whereas DNA replication occurred for all the other serotypes. Co-infection of CV1 cells with SV40 and Ad3 (or Ad31) resulted in the inhibition of SV40 DNA synthesis, as well as cellular DNA synthesis. The inhibition was not related to adenovirus DNA replication, since SV40 did not complement the Ad3/Ad31 replication defective function. Similar results were obtained in coinfected BSC and MK2 simian cell lines. Inhibition of Ad2ND1 DNA synthesis and gene expression also occurred in co-infection of simian cells with nondefective Ad2ND1 hybrid and defective Ad3/Ad31. In permissive human cell lines (HeLa or KB) co-infected with Ad2 and Ad3 (or Ad31), a dominant, inhibitory effect of Ad3 (or Ad31) over Ad2 was also observed. The inhibition appeared to function stoichiometrically and not catalytically, and to involve early adenovirus gene products. In both simian and human cells a hierarchy of dominance appeared between serotypes belonging to different subgroups. The degree of inhibitory effect occurred in the following decreasing order: Ad3 and Ad7 (subgroup B), Ad9 (D), Ad4 (E), Ad31 (A), Ad2 and Ad5 (C).