Specific Interferon-Gamma Producing CD4+ and CD8+ T Cells After Autologous EBV-B Stimulation: The Necessity of Restimulation

The response of T cells to produce interferon-γ, to proliferate and to become cytotoxic after specific stimulation with low dose (2%) autologous EBV-B cells was investigated in 15 EBV seropositive and five seronegative patients. A significantly higher number of interferon-γ producing cells (56 ± 24 per 10⁵ T cells) were found in a spot ELISA in EBV positive than in EBV negative patients (7 ± 2 spots, P<0.01) and it was only found with restimulation after 5–12 days of primary culture. No correlation was found between the extent of interferon-γ production, cytotoxicity or profileration. Specificity of EBV-induced interferon-γ production was demonstrated by comparison of the response to allogeneic EBV-B cells or IL-2 in the reslimulation phase. The response was stronger in CDS⁺ T cells than in CD4⁺ T cells and could be blocked in the restimulation phase with HLA class I and class II antiserum, respectively.