IgG1-mediated clearance of incompatible mRBCs. Wild-type FVB/NJ mice were passively immunized intraperitoneally with the indicated amounts of purified 10F7, an anti–hGPA IgG1 mAb; 16 hours later they were transfused with ⁵¹Cr-labeled wild-type (ie, (−) control) or hGPA-Tg-mRBCs, and 24-hour RBC survivals were quantified. Results are recorded as percentage of transfused RBCs remaining in the vasculature after 24 hours for groups of 2 to 5 mice (mean ± 1 SD). These results show that incompatible hGPA-Tg-mRBCs were cleared from the circulation of mice in proportion to the dose of purified 10F7 mAb that they received.