TABLE 4.
Intracellular virus neutralization by IgA antibodies to F, N, and H and by antibody combinationsa
| IgA MAb (μg/ml) | Apical supernatant
|
Cell lysate
|
||
|---|---|---|---|---|
| Virus titer (10−3 PFU/ ml) | % Reduction of virusb | Virus titer (10−5 PFU/ ml) | % Reduction of virusb | |
| Anti-H (100) | 0.48 ± 0.04c | 98 | 0.93 ± 0.16c | 84 |
| Anti-F (100) | 18.9 ± 1.80d | 26 | 2.52 ± 0.28c | 57e |
| Anti-N (100) | 16.8 ± 2.40d | 34 | 2.25 ± 0.26c | 62e |
| Anti-H (50) | 6.12 ± 0.69c | 76 | 1.70 ± 0.39c | 71 |
| Anti-H (33) | 8.06 ± 0.52c | 68 | 1.96 ± 0.46c | 66 |
| Anti-H (50) + anti-F (50) | 2.05 ± 0.79c | 92 | 2.13 ± 0.51c | 64e |
| Anti-H (50) + anti-N (50) | 1.67 ± 0.53c | 93 | 2.28 ± 0.76c | 61e |
| Anti-F (50) + anti-N (50) | 25.2 ± 2.40d | 1 | 3.91 ± 0.65c | 33e |
| Anti-H (33) + anti-F (33) + anti-N (33) | 3.29 ± 0.77c | 87 | 2.33 ± 0.54c | 60e |
| Irrelevant (100) | 25.5 ± 4.90 | 0 | 5.81 ± 1.02 | 1 |
| None | 25.5 ± 5.10 | 0 | 5.85 ± 0.28 | 0 |
a
Experiments were repeated on at least three occasions with similar results. Results of a representative experiment are shown. Data are mean ± standard deviations (n = 3).
b
Compared to no-antibody control.
c
Mean virus titers were significantly lower (P < 0.01) than those from cells exposed to no antibody.
d
Mean virus titers were not significantly lower (P > 0.05) than those from cells exposed to no antibody.
e
A significantly smaller percent reduction (P < 0.04) than that with anti-H alone at 100 μg/ml.