IL-10 producing B cells partially restore E2-mediated protection against EAE in PD-L1 deficient mice.

Women with multiple sclerosis (MS) often experience clinical improvement during pregnancy, indicating that sex hormones might have therapeutic effects in MS. Our previous studies have demonstrated that B cells and PD-L1 are crucial for E2 (17β-estradiol)-mediated protection against experimental autoimmune encephalomyelitis (EAE). We here demonstrate that the transfer of IL-10(+) B cells into E2-treated PD-L1(-/-) mice after EAE induction could partially restore E2-mediated protection and decrease the frequency of pro-inflammatory cells in the CNS compared to E2/saline treated PD-L1(-/-) mice. Hence, co-administration of IL-10(+) B cells and E2 might have a powerful therapeutic potential for treatment of EAE.