Age-associated B cells are long-lasting effectors that restrain reactivation of latent γHV68

Age-associated B cells (ABCs; CD19+CD11c+T-bet+) are a unique population that are increased in an array of viral infections, though their role during latent infection is largely unexplored. Here, we use murine gammaherpesvirus 68 ({gamma}HV68) to demonstrate that ABCs remain elevated long-term during latent infection and express IFN{gamma} and TNF. Using a strain of {gamma}HV68 that is cleared following acute infection, we show that ABCs persist in the absence of latent virus, though their expression of IFN{gamma} and TNF is decreased. With a fluorescent virus we demonstrate that ABCs are infected with {gamma}HV68 at similar rates to other previously activated B cells. We find that mice without ABCs display defects in anti-viral IgG2a/c antibodies and are more susceptible to {gamma}HV68 reactivation when challenged with heterologous infection. Together, these results indicate that ABCs are a persistent effector subset during latent viral infection that restrains {gamma}HV68 reactivation.