Figure 4. B cell MHCII antigen presentation mediates optimal immunity to N. brasiliensis.

Surface expression of CD28 and TCR on CD4⁺ T cells and CD86 and MHCII on B cells in naive (A) and N. brasiliensis re-infected (B) IL-4Rα^−/lox mice and MB1 ^CreIL-4Rα^−/lox mice was established by FACS analysis. Histograms: filled gray: isotype control, thin line: IL-4Rα^−/lox, thick black line: MB1^CreIL-4Rα^−/lox. Contributions by MHCII dependent antigen presentation were demonstrated by isolating WT or MHCII^−/− B cells from naive or infected mice then adoptively transferring into naive C57BL/6 mice (C). Mice were then infected with 500xL3 N. brasiliensis larvae and worm burdens were established at day 5 post infection (D). Mediastinal lymph node IL-13 responses were established by intracellular FACS staining in CD4⁺ T-cell and B220⁺ B cell populations (E). MHC dependent antigen presentation was confirmed by isolating WT and BALB/b B cells from naive or infected mice adoptively transferring into naive BALB/c mice. Mice were then infected with 500xL3 N. brasiliensis larvae and worm burdens were established at day 5 post infection (F). Mediastinal lymph node IL-13 responses were established by intracellular FACS staining in CD4⁺ T-cell and B220⁺ B cell populations (G). Data is representative of 2 independent experiments. n = 4–6 mice per group.