Interferon‐γ–Mediated Antiviral Immunity against Orthopoxvirus Infection Is Provided by γδ T Cells

Abstract
To the Editor —Abate et al. [1] reported increases in the numbers of vaccinia virus (VV)–responding CD4+ and CD8+ T cells in recipients of smallpox vaccine, compared with those in nonvaccinated control subjects. The population of interferon (IFN)–γ–producing γδ T cells was also expanded in vaccinated persons, suggesting that, in addition to CD4+ and CD8+ αβ T cells, γδ T cells might be involved in orthopoxvirus-induced immune responses