Figure 3.

MOG-specific antibodies partially restored susceptibility to rhMOG-induced EAE in B–MHC II^−/− mice. (A) Sera were obtained from B–MHC II^−/− and B–MHC II^+/+ mice on day 14 after immunization with MOG p35–55, rmMOG, or rhMOG. Total anti-MOG IgG levels (µg/ml) determined by ELISA (1:1,000 dilution) are shown (n = 5 mice/group). Horizontal bars indicate mean. (B) Numbers indicate the percentages of splenic Bcl-6⁺CXCR5⁺ Tfh cells (pregated on CD4⁺CD44⁺ICOS⁺PD-1⁺ T cells) evaluated by intracellular FACS staining 14 d after EAE induction with rhMOG. (C) B–MHC II^−/− and B–MHC II^+/+ mice were immunized with rhMOG (n = 4–6/mice/group), and clinical scores were monitored at the indicated days after immunization. When B–MHC II^+/+ mice showed EAE signs (score ∼2.0), B–MHC II^−/− mice received i.p. injections of 150 µg of either anti-MOG 8-18C5 mAb (closed triangles) or an equal amount of anti-OVA 1B7.11 mAb (closed circles) three times at 48-h intervals. Results are representative of two independent experiments. In one experiment, sera from IgH^MOG-ki mice and non-Tg littermate mice were used in lieu of 8-18C5 and 1B7.11 mAbs. (D) BM chimera mice with MHC II deficiency restricted to MOG-specific B cells from IgH^MOG-ki mice were generated by reconstituting C57BL/6J mice with mixed BM from J_HT + IgH^MOG-ki mice or J_HT + IgH^MOG-ki mice backcrossed onto the MHC II^−/− background. Chimera mice with MOG-specific MHC II–deficient B cells (IgH^MOG-ki/MHC II^−/−) or MOG-specific MHC II–competent B cells (IgH^MOG-ki/MHC II^+/+) were immunized with MOG p35–55, rmMOG, or rhMOG (n = 5 mice/group), and clinical scores were monitored at the indicated days after immunization. Data shown are representative of four independent experiments. Mean disease score ± SEM is shown for all experiments displayed. For all experiments: **, P < 0.01 by Mann–Whitney U test.