KEL-specific RBC clearance varies by antigen density and passive immunization. (A) Schematic for experimental design. (B) Representative flow plot illustrating gating strategy of DiI-labeled KEL⁺ RBCs and DiO-labeled KEL-negative (KEL⁻) RBCs. (C) KEL⁺ RBC survival at 10 minutes, and 1, 2, 4, 6, and 24 hours posttransfusion in WT B6 mice immunized with a phosphate-buffered saline (PBS) control (orange) or with low (lo, green), medium (med, blue), or high (hi, red) dosages of anti-KEL antibodies (αKEL). (D) KEL^lo (green), KEL^med (blue), or KEL^hi (red) RBC survival in WT B6 mice at 10 minutes, and 1, 2, 4, 6, and 24 hours after transfusion. The same RBC survival data are plotted in 2 ways to demonstrate the key variables of antigen density (C, density-specific) and concentration of passive immunization (D, immunization-specific). Error bars represent mean ± standard error of the mean (SEM). n = 5-7 mice per group. (C-D) represents data reproduced 3 times.