TABLE 2.
NIH trial 2: antibody responses and the outcome of P. falciparum challenge in A. nancymai immunized with the 3D7 or FVO version of yP30P2MSP119 in CFA or Montanide ISA 720
| Vaccine | Aotus no. | Prepatent perioda | % Peak parasitemiab | Day of treatmentc | Outcome of infectiond | IIFe | Estimated ELISA titerf
|
|
|---|---|---|---|---|---|---|---|---|
| Pre | Post | |||||||
| yP30P2MSP119 | 2068 | 16 | 0.5 | None | Self-clear | 106 | 15,205 | 24,658 |
| FVO in CFA | 2104 | 16 | 0.1 | None | Self-clear | 106 | 58,155 | 68,384 |
| 2084 | 16 | 6.0 | 28 (P) | Virulent | 105 | 16,292 | 8,750 | |
| 2095 | 22 | 1.0 | None | Self-clear | 106 | 2,407 | 2,137 | |
| yP30P2MSP119 | 2062 | 20 | 0.5 | 25 (A) | Virulent | 106 | 19,499 | 38,249 |
| 3D7 in CFA | 2110 | 22 | 0.1 | None | Self-clear | 105 | 33,101 | 29,279 |
| 2082 | 21 | 0.2 | None | Self-clear | 106 | 26,978 | 36,514 | |
| 2119 | 16 | 1.0 | 28 (A) | Virulent | 106 | 29,077 | 21,510 | |
| TBV25H in CFA | 2032 | 18 | 5.0 | 18 (P) | Virulent | <102 | 15 | 120 |
| 2100 | 22 | 8.0 | 22 (P) | Virulent | <102 | 24 | 28 | |
| 2122 | 22 | 6.0 | 22 (P) | Virulent | <102 | 12 | 26 | |
| 2107 | 21 | 5.0 | 27 (P) | Virulent | <102 | 8 | 22 | |
| yP30P2MSP119 | 2091 | 15 | 5.0 | 18 (P) | Virulent | 103 | 143 | 0 |
| FVO in Montanide ISA 720 | 2101 | 15 | 1.0 | 26 (A) | Virulent | 104 | 776 | 688 |
| 2118 | None | 0.0 | None | Self-clear | 103 | 3,493 | 1,911 | |
| 2123 | 15 | 6.0 | 19 (P) | Virulent | 103 | 3 | 3 | |
| TBV25H in Montanide ISA 720 | 2027 | 16 | 1.0 | None | Self-clear | <102 | ND | ND |
| 2036 | 15 | 6.0 | 19 (P) | Virulent | <102 | ND | ND | |
| 2097 | 16 | 10.0 | 27 (P) | Virulent | <102 | ND | ND | |
| 2094 | 15 | 0.05 | None | Self-clear | <102 | ND | ND | |
Day of the first appearance of detectable parasitemia after parasite challenge.
Highest percentage of infected RBCs observed following parasite challenge.
Day monkeys received treatment with mefloquine to cure parasitemia. (A), treatment given for severe anemia (hematocrit below 25%); (P), treatment given for parasitemia above 25%.
Self-clear, infection cleared after reaching a low-grade parasitemia; virulent, above 5% parasitemia requiring treatment.
Reaction against the FVO strain of P. falciparum. Sera were taken on day 14 after the third immunization (the day of parasite challenge).
Determined at A410 of 0.5 using yMSP119 QKNG as capture antigen. Pre, sera taken on the day of parasite challenge; Post, sera taken 4 weeks after the parasite challenge; ND, not determined.