Biological sex affects vaccine efficacy and protection against influenza in mice

Abstract

Significance: Biological sex is typically not considered in the evaluation of vaccine responses and protection against infection. We show that female mice mount greater humoral and cell-mediated immune responses to influenza infection and vaccination than males. Females can rely solely on antibody for protection following vaccination, which is associated with greater expression of toll-like receptor 7 ( Tlr7 ) caused by epigenetic mechanisms in B cells from females. Deletion of Tlr7 reduces sex differences in vaccine-induced antibody responses and protection. The increased expression of Tlr7 in B cells contributes to greater antibody production in females than males, which has a functional advantage for vaccine efficacy.