Virus-Specific CD4 + and CD8 + Cytotoxic T-Cell Responses and Long-Term T-Cell Memory in Individuals Vaccinated against Polio

Abstract

ABSTRACT The presence of poliovirus (PV)-specific CD4 + T cells in individuals vaccinated against polio has been shown, but CD8 + T-cell responses have not been described. Here, we functionally characterize the CD4 + T-cell response and show for the first time that dendritic cells and macrophages can stimulate PV-specific CD8 + T-cell responses in vitro from vaccinees. Both CD4 + T and CD8 + T cells secrete gamma interferon in response to PV antigens and are cytotoxic via the perforin/granzyme B-mediated pathway. Furthermore, the T cells also recognize and kill Sabin 1 vaccine-infected targets. The macrophage-stimulated CD4 + T and CD8 + T cells most likely represent memory T cells that persist for long periods in vaccinated individuals. Thus, immunity to PV vaccination involves not only an effective neutralizing antibody titer but also long-term CD4 + and CD8 + cytotoxic T-cell responses.