B-Cell Control of Regulatory T Cells in Friend Virus Infection

B lymphocytes have well-established effector roles during viral infections, including production of antibodies and functioning as antigen-presenting cells for CD4+ and CD8+ T cells. B cells have also been shown to regulate immune responses and induce regulatory T cells (Tregs). In the Friend virus (FV) model, Tregs are known to inhibit effector CD8+ T-cell responses and contribute to virus persistence. Recent work has uncovered a role for B cells in the induction and activation of Tregs during FV infection. In addition to inducing Tregs, B cell antibody production and antigen-presenting cell activity is a target of Treg suppression. This review focuses on the dynamic interactions between B cells and Tregs during FV infection. [Display omitted] •B cells induce Treg activation and proliferation during FV infection.•Activated B cells function as APCs of cytotoxic CD8+ T cells and produce antiviral antibodies.•Tregs induced by B cells inhibit B-cell maturation into APCs and inhibit CD8+ T-cell responses.•Tregs induced by B cells inhibit B-cell class switching and antibody production.