TABLE 1.
Anti-Pfs25 antibody responses of sera from immunized rhesus monkeys determined by ELISAa
| Group (treatment) or parameter | Monkey no. | Antibody titer
|
||
|---|---|---|---|---|
| Post 4th DNA immunization | Post heterologous protein boost | 6 mo after heterologous protein boost | ||
| 1 (VR1020/25, 0.5 mg) | M1 | 500 | 80,000 | 40,000 |
| M2 | 16,000 | >1,280,000 | 320,000 | |
| M3 | 16,000 | >1,280,000 | 160,000 | |
| M4 | 16,000 | >1,280,000 | 20,000 | |
| Mean ± SEM | 12,125 ± 3,875 | 980,000 ± 300,000 | 135,000 ± 69,000 | |
| 2 (VR1020/25, 1.0 mg) | M5 | 32,000 | >1,280,000 | 160,000 |
| M6 | 32,000 | >1,280,000 | 80,000 | |
| M7 | 16,000 | 640,000 | 40,000 | |
| M8 | 4,000 | 320,000 | 160,000 | |
| Mean ± SEM | 21,000 ± 6,800 | 880,000 ± 240,000 | 110,000 ± 30,000 | |
| 3 (VR1020/27-25, 0.5 mg) | M9 | 32,000 | 640,000 | 80,000 |
| M10 | 16,000 | 320,000 | 80,000 | |
| M11 | 16,000 | >1,280,000 | 20,000 | |
| M12 | 1,000 | 320,000 | 10,000 | |
| Mean ± SEM | 16,250 ± 6,300 | 640,000 ± 226,300 | 47,500 ± 18,900 | |
| 4 (VR1020/27-25, 1.0 mg) | M13 | 1,000 | 640,000 | 40,000 |
| M14 | 1,000 | 320,000 | 10,000 | |
| M15 | 32,000 | >1,280,000 | 160,000 | |
| M16 | 16,000 | >1,280,000 | 160,000 | |
| Mean ± SEM | 12,500 ± 7,400 | 880,000 ± 240,000 | 92,500 ± 39,500 | |
| 5 (control) (VR1020, 0.5 mg) | M17 | 0 | 320,000 | 80,000 |
| M18 | 0 | 160,000 | 80,000 | |
| M19 | 0 | 160,000 | 40,000 | |
| Mean ± SEM | 213,333 ± 53,000 | 66,700 ± 13,000 | ||
a
ELISA was performed by using sera taken 7 weeks after the fourth DNA immunization (groups 1 to 5) and 3 weeks and 6 months after a protein boost (groups 1 to 5). Titers represent reciprocal serum dilutions. Endpoint titers were defined as serum dilutions giving an absorbance higher than the average OD at 405 nm of preimmune serum plus 3 SD. Comparison of antibody titers of each group to those of the control group was done by one-way ANOVA test. Comparison of antibody titers over the time for each monkey was done by mixed ANOVA.