Table 5.
Antibodies to PfCSP, PfEXP1, and PfMSP1 by ELISA in sera collected 28 days after administration of PfSPZ Challenge as compared with in preinjection sera
| Group | PfCSP | PfEXP1 | PfMSP1 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Net OD 1.0 ≥ 50 (±total) | Mean net OD 1.0 of positives | OD 1.0 ratio ≥ 2.5 (±total) | Mean OD 1.0 ratio of positives | Overall positives (±total)* | Net OD 1.0 ≥ 50 (±total) | Mean net OD 1.0 of positives | OD 1.0 ratio ≥ 2.5 (±total) | Mean OD 1.0 ratio of positives | Overall positives (±total)* | Net OD 1.0 ≥ 50 (±total) | Mean net OD 1.0 of positives | OD 1.0 ratio ≥ 2.5 (±total) | Mean OD 1.0 ratio of positives | Overall positives (±total)* | |
| A | 2/4 | 143 | 1/4 | 10.2 | 1/4 | 4/4 | 3,302 | 4/4 | 40.0 | 4/4 | 1/4 | 139 | 4/4 | 43.0 | 1/4 |
| B | 1/4 | 105 | 1/4 | 3.3 | 1/4 | 3/4 | 2,306 | 3/4 | 11.1 | 3/4 | 2/4 | 126 | 3/4 | 93.0 | 2/4 |
| C | 3/5 | 376 | 1/5 | 7.5 | 1/5 | 5/5 | 1,728 | 4/5 | 29.9 | 4/5 | 4/5 | 202 | 5/5 | 52.8 | 4/5 |
| D | 1/5 | 523 | 2/5 | 8.0 | 1/5 | 2/5 | 3,964 | 3/5 | 27.7 | 2/5 | 0/5 | 1 | 0/5 | - | 0/5 |
| E | 3/5 | 746 | 3/5 | 105.0 | 3/5 | 4/5 | 683 | 2/5 | 13.5 | 2/5 | 2/5 | 460 | 2/5 | 247.8 | 2/5 |
| F | 5/5 | 517 | 3/5 | 17.9 | 3/5 | 4/5 | 7,065 | 4/5 | 60.8 | 4/5 | 5/5 | 367 | 5/5 | 368.4 | 5/5 |
| 10/28 | 19/28 | 14/28 | |||||||||||||
PfCSP = Plasmodium falciparum circumsporozoite protein; PfEXP1 = P. falciparum exported protein 1; PfMSP1 = P. falciparum merozoite surface protein 1; PfSPZ = P. falciparum sporozoite; ELISA; enzyme-linked immunosorbent assay; OD = optical density.
*
An individual was considered to have developed antibodies if the net OD 1.0 was ≥ 50 and the OD 1.0 ratio was ≥ 2.5 (see Methods for definitions).