KELIg prevents alloimmunization independently of recipient CD4⁺ T cells. (A) General experimental design: recipients depleted of CD4⁺ T cells were transfused with KEL RBCs in the presence or absence of KELIg, and anti-KEL IgG alloimmune responses were measured longitudinally in serum posttransfusion. (B) Total anti-KEL IgG measured in the serum of recipients following a KEL RBC transfusion in the absence of KELIg, or (C) in the presence of KELIg. These data are representative of 3 independent experiments with 3 to 5 mice per group per experiment (in total, 11 and 11 mice were studied across 3 experiments in panel B with the same number studied in panel C). There were no statistically significant differences between groups; error bars indicate standard deviation between individual mice. MFI, mean fluorescence intensity.