Interferon production by Epstein-Barr virus in human mononuclear leukocytes

Interferon (IFN) production following exposure to Epstein-Barr virus (EBV) was studied in primary human mononuclear leukocytes. When the leukocytes were exposed to EBV (strain B95-8 or P3HR-1) the IFN level reached a maximum 24 h after exposure to the virus, and a gradual decrease followed. A linear relationship was obtained between the input dose of EBV and the IFN titre. The IFN inducibility of leukocytes did not correlate with the EBV infectibility. IFN was also induced by u.v.-inactivated EBV and heat-inactivated EBV, but not by neutralized virus. IFN inducibility varied among adult donors, but there was no significant difference between EBV-seropositive and -seronegative groups. The response of cord blood leukocytes, however, was lower than that of the cells from adults. The activity of all IFN samples in this study was stable to acid and heat and exclusively neutralized by anti-human IFN-alpha. B cells, T cells and NK cells all produced IFN in response to EBV, but monocytes did not.