Induction of epstein-barr virus-associated early antigen in different lymphoid cell lines with ultraviolet-irradiated P3HR-1 virus

Abstract

Abstract High-titer stocks of the P3HR-1 variant of Epstein-Barr virus (EBV), which had been purified to remove substantial amounts of uv-absorbing impurities, were exposed to various doses of radiation at 254 nm. The residual early antigen (EA)-inducing potential of the irradiated virus was quantitated on different lymphoid cell lines. Infection of the Raji and Daudi cell lines, which contain multiple copies of the EBV genome in latent form, gave multihit survival curves for expression of EA. In contrast, infection of BJA and Ramos cells, which are two rare human B-cell lines which do not contain detectable amounts of EBV-DNA, gave single-hit viral survival curves. Moreover, the uv dose for 37% survival of the EA-inducing potential of the virus preparation was 23 J m−2 when tested on the genome-negative cell lines, and 300 J m−2 when the Raji and Daudi lines were superinfected. The data are consistent with a requirement of an intact EBV genome for EA expression in genome-negative cells, while resident viral genomes appear to function in the rescue of uv-inactivated superinfecting genomes in the EBV-carrying cell lines.