Anti-KEL antibodies induce complement fixation on KEL^lo, KEL^med, and KEL^hiRBCs. (A-D) KEL^lo (green), KEL^med (blue), and KEL^hi (red) RBCs were examined for active complement components (C3/C3b/iC3b) deposition by flow cytometry at 10 minutes, and 1, 2, 4, 6, and 24 hours posttransfusion into low, medium (med), or high (hi) αKEL immunized recipients. (E-H) KEL^lo (green), KEL^med (blue), and KEL^hi (red) RBCs were examined for total complement component 3 (C3) deposition by flow cytometry at 10 minutes, and 1, 2, 4, 6, and 24 hours posttransfusion into low, medium (med), or high (hi) αKEL immunized recipients. *Significance indicated vs value at 10 minutes posttransfusion. P < .05. Error bars represent mean ± SEM. n = 5-7 mice per group. Each panel represents data reproduced 3 times.