Table I. Invasion of transfected parasites into enzyme-treated erythrocytes.
| Erythrocyte treatmenta | Parasiteb |
|||||
|---|---|---|---|---|---|---|
| 3D7 | 3D7Δ2b1 | 3D7Δ2b2 | 3D7Δ2a1 | 3D7Δ2a2 | D10 | |
| Low trypsin/chymotrypsin | 22.8 ± 7.6 | 70.5 ± 7.7c | 65.5 ± 12.9c | 18.1 ± 4.8 | 14.1 ± 2.6 | 58.0 ± 5.8c |
| Neuraminidase/low trypsin | 23.0 ± 6.9 | 3.9 ± 0.6c | 3.3 ± 0.4c | 24.5 ± 6.0 | 21.9 ± 4.9 | 10.26 ± 2.3c |
| Chymotrypsin | 67.0 ± 9.1 | 105.3 ± 9.4c | 113.9 ± 14.3c | 70.1 ± 10.1 | 65.3 ± 15.1 | 99.8 ± 5.9c |
| Low trypsin | 93.5 ± 9.0 | 63.3 ± 7.8c | 61.7 ± 9.7c | 80.8 ± 6.7 | 93.0 ± 14.0 | 85.9 ± 7.3 |
| Neuraminidase | 79.2 ± 8.5 | 58.2 ± 8.7c | 47.5 ± 6.3c | 73.9 ± 7.1 | 82.7 ± 14.9 | 74.3 ± 11.4 |
aRed blood cells were treated with the enzymes indicated, as described in Materials and methods, before testing in merozoite invasion assays.
bFigures are the percentage invasion compared with invasion of 3D7 into untreated blood cells, and errors are 95% confidence limits. The data were from 6–14 independent experiments all carried out in triplicate. In the experiments, the starting parasitemia was 0.5% and the final parasitemia was between 3 and 6% for untreated erythrocytes.
cSignificantly different invasion when compared with 3D7.