IgM-mediated clearance of incompatible hGPA-Tg-mRBCs
| Experiment no. . | mAb . | mRBCs transfused . | No. of mice . | Percent 2-h RBC survival, mean ± 1 SD . | Percent 24-h RBC survival, mean ± 1 SD . | Urine absorbance at 414 nm . |
|---|---|---|---|---|---|---|
| 1 | E4 | Wild-type | 4 | 91.3 ± 6.3 | ND | 0.04, 0.05, 0.10, 0.06 |
| 1 | E4 | hGPA-Tg | 4 | 19.1 ± 2.0 | ND | 0.28, 1.63, 0.74, 0.77 |
| 2 | None | hGPA-Tg | 3 | 99.6 ± 1.1 | 98.9 ± 3.9 | ND |
| 2 | E4 | hGPA-Tg | 5 | 29.4 ± 5.1 | 23.2 ± 3.2 | ND |
| Experiment no. . | mAb . | mRBCs transfused . | No. of mice . | Percent 2-h RBC survival, mean ± 1 SD . | Percent 24-h RBC survival, mean ± 1 SD . | Urine absorbance at 414 nm . |
|---|---|---|---|---|---|---|
| 1 | E4 | Wild-type | 4 | 91.3 ± 6.3 | ND | 0.04, 0.05, 0.10, 0.06 |
| 1 | E4 | hGPA-Tg | 4 | 19.1 ± 2.0 | ND | 0.28, 1.63, 0.74, 0.77 |
| 2 | None | hGPA-Tg | 3 | 99.6 ± 1.1 | 98.9 ± 3.9 | ND |
| 2 | E4 | hGPA-Tg | 5 | 29.4 ± 5.1 | 23.2 ± 3.2 | ND |
Wild-type C57BL/6 mice were passively immunized intravenously with 100 μg of the purified E4 IgM anti-hGPA mAb, or with the same volume of NS, 2 minutes prior to transfusion with 51Cr-labeled wild-type FVB/NJ mRBCs or hGPA-Tg-mRBCs. The RBC survival at 2 and 24 hours was then determined as described in “Materials and methods.” In addition, scanning wavelength spectrophotometry was used to identify hemoglobin (which has a characteristic absorption peak at 414 nm) in urine collected from the bladder at autopsy. Experiments 1 and 2 were performed on different days with different lots of mAb E4; the mice were humanely killed at 2 hours after transfusion in experiment 1 and at 24 hours after transfusion in experiment 2. Bladder urine obtained at autopsy in all mice in experiment 2 was clear yellow; therefore, the absorbance was not determined (ND).