C3b(i) and mAb 3E7 bind to CD20+ cells during C/RTX opsonization
| Cells and incubation medium . | Molecules bound per cell . | |
|---|---|---|
| C3b(i)* . | Anti-C3b(i) mAb 3E7† . | |
| Raji cells‡ | ||
| NHS | 300 000 ± 150 0001-155 (18) | NA |
| NHS/RTX | 610 000 ± 190 000 (18) | NA |
| NHS/RTX/mAb 3E7 | 1400 000 ± 500 000 (13) | 890 000 ± 220 000 (6) |
| NHS/mAb 3E7 | 680 000 ± 340 000 (14) | 420 000 ± 190 000 (6) |
| ARH-77 cells1-153 | ||
| NHS | 150 000 ± 60 000 (10) | NA |
| NHS/RTX | 790 000 ± 230 000 (10) | NA |
| NHS/RTX/mAb 3E7 | 930 000 ± 240 000 (9) | 1100 000 ± 200 000 (3) |
| NHS/mAb 3E7 | 370 000 ± 110 000 (9) | 240 000 ± 60 000 (3) |
| Cells and incubation medium . | Molecules bound per cell . | |
|---|---|---|
| C3b(i)* . | Anti-C3b(i) mAb 3E7† . | |
| Raji cells‡ | ||
| NHS | 300 000 ± 150 0001-155 (18) | NA |
| NHS/RTX | 610 000 ± 190 000 (18) | NA |
| NHS/RTX/mAb 3E7 | 1400 000 ± 500 000 (13) | 890 000 ± 220 000 (6) |
| NHS/mAb 3E7 | 680 000 ± 340 000 (14) | 420 000 ± 190 000 (6) |
| ARH-77 cells1-153 | ||
| NHS | 150 000 ± 60 000 (10) | NA |
| NHS/RTX | 790 000 ± 230 000 (10) | NA |
| NHS/RTX/mAb 3E7 | 930 000 ± 240 000 (9) | 1100 000 ± 200 000 (3) |
| NHS/mAb 3E7 | 370 000 ± 110 000 (9) | 240 000 ± 60 000 (3) |
Values shown are averages ± SD. Numbers in parentheses indicate number of determinations. NA indicates not applicable.
Molecules bound were measured by indirect RIA based on probing with125I-anti-C3b(i) mAb 7C12.
125I-anti-C3b(i) mAb 3E7 was used directly.
Either mAb singly or the combination gave more C3b(i) deposition than NHS alone (P < 10−3). RTX/mAb 3E7 gave more C3b(i) deposition than either mAb alone (P < 10−3). More mAb 3E7 was bound in the presence of RTX (P = 3 × 10−3).
Either mAb singly or the combination gave more C3b(i) deposition than NHS alone (P < 10−3). The combination gave more C3b(i) deposition than mAb 3E7 alone (P < 10−3). More mAb 3E7 was bound in the presence of RTX (P = 2 × 10−3).
Background level of binding of C3b(i) to the Raji (and ARH-77) cells in NHS has been previously reported.12 13 Raji cells in NHS activate C, but less C3b(i) is bound than is observed in the presence of RTX.