Exposure to antigen-specific antibodies induces antigen-specific antibody-mediated immunesuppression. WT mice were treated with PBS (no antibody), anti-KEL, or anti-HEL before exposure to HOD × KEL RBC (A) followed by evaluation of anti-KEL IgM (B), anti-KEL IgG antibodies (C), anti-HOD IgM (D), or anti-HOD IgG antibodies (E) at the time points indicated. Means ± SD shown. ****P < .0001, ***P < .001, **P < .01, *P < .05, and ns by 1-way ANOVA with Tukey multiple comparison test. Data shown include 5 mice per group and are representative of 3 independent experiments.