Inhibition of Epstein-Barr virus infection in vitro by recombinant human interferons alpha and gamma.

The inhibitory effects of pure recombinant human interferons alpha A and gamma (reIFN-alpha A and -gamma) on Epstein-Barr virus (EBV) infection of a human EBV-negative B cell line, BJAB, and of normal adult B lymphocytes were studied. With pretreatment for 24 h, both types of reIFNs were effective in suppressing the production of EBV specific nuclear antigen (EBNA-1) in BJAB cells 24 h after EBV-infection, as determined by the immunoblotting technique. ReIFN-alpha A was, however, a much more potent inhibitor than reIFN-gamma. With treatment starting 1 h after EBV infection, both types of reIFNs were less effective in the suppression of EBNA production. Neither of the reIFNs showed any inhibitory effect on EBNA production in the latently EBV-infected cell lines, Raji and Daudi. These results suggest that reIFNs act in the early phase of EBV infection. Both types of reIFNs were also effective in inhibiting EBV infection of normal adult B lymphocytes as demonstrated by a reduction both in [3H]thymidine incorporation 6 days after EBV infection and in the total number of proliferating cells 21 days after EBV infection. Again, reIFN-alpha A showed a greater inhibitory effect than reIFN-gamma. We also showed that in BJAB cells, reIFN-alpha A strongly induced (2'-5')oligoadenylate synthetase activity, whereas reIFN-gamma increased the surface expression of HLA class I antigens.