IgG-mediated clearance of transfused incompatible hGPA-Tg RBCs. WT C57BL/6 mice were passively immunized with 2 mg 10F7 anti-hGPA IgG1 Mab (A), 100 μg 6A7 anti-hGPA IgG1 Mab (B), or 2 mg anti-HEL IgG1 Mab (C). Mice were then transfused with DiO-labeled WT C57BL/6 RBCs (as an internal negative control) and with either DiI-labeled incompatible hGPA-Tg RBCs (△) or DiI-labeled compatible WT FVB/NJ RBCs (▲). RBC survival, as percentage of PBS control (ie, nonimmunized) mice, was quantified by flow cytometry at the indicated time points. Five mice were evaluated at each time point; the means plus or minus 1 SD are provided. The results shown are from one representative experiment (from a total of 4 replicates). *P < .05. Urine was obtained at the 20-hour time point from 4 mice receiving incompatible hGPA-Tg RBC transfusions (●) and 9 mice receiving compatible WT FVB/NJ RBC transfusions (x). Representative spectra from one mouse from each group are shown (D).