Resting B Cells Are Not Antigen-Presenting Cells in the Induction of Oral Tolerance of Specific Th2 Immune Responses in Mice

Abstract

Background: It has been shown that antigen presentation by resting B cells can induce tolerance to intravenously administered protein antigens, but the role of resting B cells in the induction of oral tolerance is unclear. Methods: Mice continuously treated since birth with rabbit anti-mouse IgM serum for 5 weeks were depleted of B cells. When 4 weeks old, B cell-depleted mice drank 10% chicken egg white (EW) for 5 days. Ten weeks later, they were immunized with 10 μg of ovalbumin in alum and their T helper 2 (Th2) immune responses were tested. Results: Th2 cell-mediated IgE and IgG1 antibody responses and spleen cell production of IL-4 and IL-5 were suppressed by prior EW feeding during anti-IgM treatment. When anti-IgM-treated spleen cells collected 1 week after EW ingestion were transferred to naïve recipients, active suppression of Th2 immune responses was also demonstrated. Conclusions: Although resting small B cells aggregate in the mantle zone of follicles of intestinal Peyer’s patches, the present data suggest that they are not antigen-presenting cells in the induction of oral tolerance of Th2 immune responses to oral antigens.