Yonago Acta medica 1996;39:99–107
Decreased Expression of Early Antigens in P3HR-1-EBV Superinfected Raji Cells Cultured in EBV-Seropositive Human Sera
Takeshi Sairenji, Patricia S. Reisert*, Robert C. Spiro* and Robert E. Humphreys*
Department of Biosignaling, Faculty of Medicine, Tottori University, Yonago 683, Japan and *Department of Pharmacology, University of Massachusetts Medical School, Worcester, MA 01655, United States
Antibody-induced change in the expression of Epstein-Barr virus (EBV) antigens was studied after P3HR-1-EBV superinfection of Raji cells. The superinfected Raji cells were cultured in medium containing fetal calf serum (FCS) and either EBV antibody-positive or -negative human sera which had been selected for low natural cytotoxic antibodies to Raji cells. At 24 postsuperinfective (psi) h the percentages of early antigen (EA)-positive cells were similar for cultures with FCS only or also with EBV antibody-positive or -negative sera. However, at 48 psi h decreased expression of EA-positive cells was observed in cultures with EBV antibody-positive sera, but not with EBV antibody-negative sera or with FCS only. This EA suppressing effect was dependent upon concentration of EBV antibody-positive human serum and related with anti-viral capsid antigen (VCA) or membrane antigen (MA) titers among effective sera. Antibody-mediated suppression of EA at 48 psi h was inhibited by treatment with phosphonoacetic acid which inhibits herpesvirus DNA replication and blocks late viral functions. These results are consistent with hypotheses that suppression of intracellular EA follows from modulation (or alteration) of MA by an anti-MA antibody and that a late viral function is required for the antibody-mediated inhibition of EA expression in this system.
Key words: Epstein-Barr virus; early antigen; membrane antigen; modulation; anti-EBV antibodies
