Table II. Effect of vaccination on bacteremia progression in NHPs inoculated ID with O. tsutsugamushi Karp.
| Bacteremiaa |
||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Vaccine Group | NHP ID | d5 | d7 | d9 | d12 | d14 | d16 | d19 | d21 | d23 | d26 | d28 | Duration of Bacteremia (days) | Start of Bacteremia (days postinoculation) | AUC of Bacteremiab | Eschar Y/N/Bc |
| Group 1 | ||||||||||||||||
| None (PBS) | 8749c | 1 | 4 | 8 | 3 | 8 | 12 | 33.5 | B (d2) | |||||||
| None (PBS) | 6741 | 3 | 4 | 10 | 67 | 103 | 4 | 13 | 7 | 435.5 | Y | |||||
| None (pVR1012) | 5671 | 2 | 7 | 14 | 43 | 1 | 11 | 9 | 157.5 | Y | ||||||
| None (pGM-CSF) | 8824 | 1 | 12 | 40 | 6 | 1 | 10 | 12 | 141 | Y | ||||||
| None (pGM-CSF) | 5199 | 2 | 11 | 65 | 570 | 91 | 14 | 4 | 15 | 9 | 1845 | Y | ||||
| None (mSEB-VRP) | 6856c | 7 | 18 | 25 | 6 | 4 | 10 | 12 | 124.5 | B (d7) | ||||||
| Group 2 | ||||||||||||||||
| Kp47/47-VRP | 5747 | 3 | 18 | 119 | 551 | 188 | 13 | 13 | 9 | 2148 | Y | |||||
| Kp47/47-VRP | 8984 | 7 | 8 | 38 | 5 | 12 | 61 | Y | ||||||||
| Group 3 | ||||||||||||||||
| pKarp47 (2 mg ×3) | 6537 | 0 | 0 | N | ||||||||||||
| pKarp47 (2 mg ×3) | 5732 | 7 | 4 | 3 | 6 | 14 | 21.5 | Y | ||||||||
| pKarp47 (1 mg ×3) | 5253c | 0 | 0 | B (d2) | ||||||||||||
| pKarp47 (1 mg ×3) | 7416 | 1 | 8 | 10 | 14 | 8 | 12 | 63 | N | |||||||
| pKarp47 (0.5 mg ×3) | 5817 | 0 | 0 | N | ||||||||||||
| pKarp47 (0.5 mg ×3) | 5601 | 13 | 5 | 5 | 5 | 19 | 28 | N | ||||||||
| Group 4 | ||||||||||||||||
| pKarp47 (2 mg ×2) +Kp47/47-VRP | 5689 | 9 | 45 | 7 | 3 | 8 | 14 | 142 | N | |||||||
| pKarp47 (2 mg ×2) +Kp47/47-VRP | 6985 | 3 | 2 | 0 | 1 | 8 | 14 | 9 | Y | |||||||
| pKarp47 (1 mg ×2) +Kp47/47VRP) | 2660 | 0 | 0 | N | ||||||||||||
| pKarp47 (1 mg ×2) +Kp47/47-VRP | 5234c | 3 | 21 | 32 | 54 | 3 | 2 | 13 | 9 | 265.5 | B (d7) | |||||
| pKarp47 (0.5 mg ×2) +Kp47/47-VRP | 5235 | 10 | 48 | 110 | 19 | 10 | 1 | 12 | 12 | 449.5 | Y | |||||
| pKarp47 (0.5 mg ×2) +Kp47/47-VRP | 7982 | 4 | 6 | 13 | 23 | 81 | 9 | 12 | 12 | 277 | Y | |||||
All unvaccinated NHPs in the control group developed bacteremia after ID challenge, whereas the period, start point, and AUC of bacteremia differed between the vaccine groups.
a
Bacteremia was measured as DNA GEs/10 μl whole blood.
b
AUC corresponds to the total sum of bacterial copy numbers during bacteremia as surrogate for the bacterial load during bacteremic dissemination phase.
c
Biopsy taken at the site of inoculation (day 2 or 7).
B, biopsy; d, day; ID, identification; N, no; Y, yes.