TABLE 2.
Transmission-blocking activity of sera from immunized rhesus monkeys determined by membrane feeding assaya
| Monkey no. treatment (group) or control | No. of infected mosquitoes/no. dissectedb | Geometric mean no. of oocysts (range) | Infectivity (% of control)c |
|---|---|---|---|
| Normal human sera | 32/33 | 21.2 (0-66) | |
| Preimmune sera | 39/40 | 17.5 (0-55) | 100 |
| M5, DNA-DNA (2) | 35/36 | 12.9 (0-89) | 74 |
| M6, DNA-DNA (2) | 42/45 | 17.3 (0-90) | 99 |
| M5, DNA-protein (2) | 21/39 | 0.9 (0-7)d | 5 |
| M6, DNA-protein (2) | 18/26 | 1.9 (0-10)d | 11 |
| M15, DNA-DNA (4) | 28/28 | 16.6 (3-48) | 95 |
| M16, DNA-DNA (4) | 46/47 | 14.8 (0-52) | 85 |
| M15, DNA-protein (4) | 33/46 | 2.1 (0-13)d | 12 |
| M16, DNA-protein (4) | 41/47 | 3.1 (0-17)d | 17 |
| M17, protein (5) | 34/35 | 6.9 (0-27)d | 39 |
| M18, protein (5) | 33/35 | 21 (0-93) | 120 |
Cultured gametocytes of P. falciparum strain NF54 were fed to A. stephensi mosquitoes at a 1:2 serum dilution. Results shown are pooled from two experiments and represent similar overall findings in six individual assays. The sera tested were collected after a fourth DNA immunization (DNA-DNA) or after a subsequent protein boost (DNA-protein).
Number of infected mosquito midguts/total number of mosquitoes dissected.
Calculated as the geometric mean oocyst number of the test group divided by that of the preimmune serum-fed group × 100.
Significantly different from preimmune serum at P < 0.05 by Mann-Whitney U test and Kruskal-Wallis one-way analysis.