TABLE 3.
Serum neutralizing antibody responses to G3 and G1 viruses in rabbits immunized parenterally with VLPs before and after oral challenge with G3 ALA rotavirus
| Inoculum | Adjuvant | P serotype | G serotype | Neutralizing GMTa (range) of sera against indicated test virus (P,b G type)
|
No. of rabbits | % Protection (range) | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| SA11 (P5B,G3)
|
ALA (P[14],G3)
|
Wa (P1A,G1)
|
|||||||||
| 0 dpc | 28 dpc | 0 dpc | 28 dpc | 0 dpc | 28 dpc | ||||||
| 2/4/6/7-VLPs | Freund’s | 5B | 3 | 77,605d (25,600–204,800) | 77,605 (25,600–204,800) | 16,890d (12,800–51,200) | 19,401 (12,800–51,200) | 1,056 (800–1,600) | 2,111 (1,600–3,200) | 5 | 89d (68–100) |
| 2/6/7-VLPs | Freund’s | NAc | 3 | 75,250d (25,600–204,800) | 87,782 (51,200–102,400) | 10,973d (3,200–51,200) | 21,945 (1,600–51,200) | 126 (<100–400) | 467 (<100–3,200) | 9 | 58d (42–100) |
| 2/4/6/7-VLPs | QS-21 | 5B | 3 | 4,222d (1,600–12,800) | 72,408 (12,800–204,800) | 1,213d (400–6,400) | 63,035 (12,800–102,400) | 50 (<100) | 1,393 (200–6,400) | 10 | 56d (31–98) |
| 2/4/6/7-VLPs | QS-21 | 5B | 1 | 200 (<100–400) | 9,701 (3,200–12,800) | 100 (<100–400) | 44,572 (12,800–102,400) | 1,600 (800–3,200) | 51,200 (25,600–102,400) | 5 | 32 (11–52) |
| 2/4/6/7-VLPs | QS-21 | 5B | 3 + 1e | 9,051 (6,400–12,800) | 86,108 (51,200–102,400) | 566 (400–800) | 51,200 (51,200–102,400) | 1,345 (800–1,600) | 60,887 (51,200–102,400) | 4 | 46 (36–73) |
| 2/6/7-VLPs | QS-21 | NA | 3 | 4,222d (1,600–12,800) | 63,035 (12,800–102,400) | 1,493d (400–3,200) | 72,408 (51,200–102,400) | 50 (<100) | 800 (<100–3,200) | 10 | 26d (0–44) |
| SA11 | QS-21 | 5B | 3 | 3,553d (3,200–6,400) | 11,593 (6,400–51,200) | 1,767d (800–3,200) | 8,604 (3,200–25,600) | 50 (<100) | 181 (<100–400) | 7 | 83d (65–100) |
| Buffer | QS-21 | NA | NA | 50d (<100) | 883 (800–1,600) | 50d (<100) | 10,159 (6,400–51,200) | 50 (<100) | 50 (<100) | 7 | 0d |
Serum neutralizing antibody measured by FFN in sera collected 0 dpc (56 dpi) and 28 dpc from rabbits immunized twice with VLPs with Freund’s adjuvant or 20 μg of QS-21, as indicated. For titers of <100, 50 was used to calculate the GMT. A GMT of 50 is considered negative. Boldface indicates fourfold GMT increase in serum neutralizing antibody titers following challenge.
P serotype is indicated where known (18). If P serotype has not been determined, P genotype (in brackets) is indicated.
NA, not applicable.
Protection and serum neutralizing antibody titers reported by Ciarlet et al. (7).
Rabbits were immunized sequentially with G3 2/4/6/7-VLPs and G1 2/4/6/7-VLPs as the first and second doses of immunogen, respectively.