Interferon-γ release assay: A simple method for detection of varicella-zoster virus-specific cell-mediated immunity

Herpes zoster is closely related to decreased varicella-zoster virus (VZV)-specific cell-mediated immunity. We validated a new assay for measuring VZV-specific immunity. We cultured the whole blood of healthy subjects with live attenuated VZV vaccine. Cultured supernatants were harvested at 24-h intervals and assayed for interferon-gamma (IFN-γ) by an enzyme-linked immunosorbent assay (ELISA). The 48-h culture was suitable for estimating IFN-γ release. IFN-γ production was stable after standing for at least 4 h at room temperature. IFN-γ production was observed in whole blood from subjects with recent VZV infection, but not in blood from subjects naïve to the virus. Thus, the IFN-γ release assay may be useful as a new surrogate assay for measuring VZV-specific immunity.