Antibody formation indicated by the Bethesda inhibitor assay
Mouse . | Pretreatment . | 2 wk . | 4 wk . | 6 wk . | 8 wk . | 10 wk . | 12 wk . |
|---|---|---|---|---|---|---|---|
| FIXKO no. 1 | 0 | 0 | 2.8 | 1.7 | 1.1 | 2.3 | 2.5 |
| FIXKO no. 2 | 0 | 0 | 1.5 | 16.0 | 16.0 | 31.2 | 34.4 |
| FIXKO no. 3 | 0 | 0 | 1.7 | 9.0 | 12.8 | 8.6 | 16.5 |
| FIXKO no. 4 | 0 | 0 | 2.6 | 6.6 | 6.8 | 4.9 | 6.0 |
| FIXKO no. 5 | 0 | 0 | 1.0 | 9.6 | 17.2 | 12.0 | 12.8 |
| All R333Q, n = 6 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Mouse . | Pretreatment . | 2 wk . | 4 wk . | 6 wk . | 8 wk . | 10 wk . | 12 wk . |
|---|---|---|---|---|---|---|---|
| FIXKO no. 1 | 0 | 0 | 2.8 | 1.7 | 1.1 | 2.3 | 2.5 |
| FIXKO no. 2 | 0 | 0 | 1.5 | 16.0 | 16.0 | 31.2 | 34.4 |
| FIXKO no. 3 | 0 | 0 | 1.7 | 9.0 | 12.8 | 8.6 | 16.5 |
| FIXKO no. 4 | 0 | 0 | 2.6 | 6.6 | 6.8 | 4.9 | 6.0 |
| FIXKO no. 5 | 0 | 0 | 1.0 | 9.6 | 17.2 | 12.0 | 12.8 |
| All R333Q, n = 6 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Plasma from gene therapy-treated mice was incubated with an equal volume of pooled normal human plasma assayed by APTT. Numbers given in Bethesda inhibitor units represent the dilution of sample plasma that results in inactivation of 50% of the factor IX activity of the normal plasma.