Table 1.
Comparison of antibody responses measured with different assays following NV infection of human volunteers (n = 18)
| Assay and parameter | Result on study day |
|||||
|---|---|---|---|---|---|---|
| Pred | 2 | 7 | 14 | 28–30 | 180 | |
| Total ELISA (IgG, IgA, IgM) | ||||||
| No. (%) seropositivea | 18 (100) | 18 (100) | 18 (100) | 18 (100) | 18 (100) | 18 (100) |
| No. (%) with seroconversionb,c | 0 (0) | 9 (50) | 18 (100) | 18 (100) | 16 (89) | |
| Geometric mean fold riseb | 1 | 4 | 94 | 128 | 17 | |
| IgG | ||||||
| No. (%) seropositivea | 16 (89) | 16 (89) | 18 (100) | 18 (100) | 18 (100) | 18 (100) |
| No. (%) with seroconversionb,c | 0 (0) | 7 (39) | 18 (100) | 18 (100) | 14 (78) | |
| Geometric mean fold riseb | 1 | 4 | 70 | 97 | 18 | |
| IgA | ||||||
| No. (%) seropositivea | 9 (50) | 10 (56) | 17 (94) | 18 (100) | 18 (100) | 18 (100) |
| No. (%) with seroconversionb,c | 1 (6) | 15 (83) | 18 (100) | 18 (100) | 13 (72) | |
| Geometric mean fold riseb | 1 | 40 | 636 | 260 | 24 | |
| IgM | ||||||
| No. (%) seropositivea | 1 | 2 (11) | 13 (72) | 15 (83) | 1 (6) | |
| No. (%) with seroconversionb,c | 2 (11) | 12 (67) | 14 (78) | 0 (0) | ||
| Geometric mean fold riseb | 1 | 24 | 33 | 1 | ||
a
Seropositive if IgG or IgA is >1.4 or >1.6 μg/ml, respectively, or ELISA reciprocal titer is >25 (total or IgM).
b
Compared to prechallenge serum titer.
c
Seroconversion is defined as a ≥4-fold rise in antibody levels between pre- and postchallenge samples.
d
Pre, prechallenge.