Table 4. VN and HI antibody responses to H1N1 viruses detected in human sera.
| Neutralization† and HI‡ antibody titer
|
|||||
|---|---|---|---|---|---|
| Serum sample* | Year of birth | 1918 HA/NA | Sw/la/30 | PR/8/34 | New Cal/99 |
| A | 1910 | 160 (80) | 40 (40) | 20 (10) | <10 (<10) |
| B | 1911 | 320 (160) | 80 (40) | 80 (20) | <10 (<10) |
| C | 1928 | 160 (160) | 160 (80) | 40 (40) | 40 (40) |
| D | 1932 | 10 (10) | <10 (<10) | 40 (20) | <10 (<10) |
| E | 1933 | 160 (80) | 80 (80) | 160 (40) | 80 |
| F | 1944 | <10 (<10) | <10 (<10) | <10 (<10) | 10 |
| G | 1962 | 10 (10) | <10 (<10) | <10 (<10) | 80 |
| H | 1966 | 20 (20) | <10 (<10) | <10 (<10) | 20 |
| I | 1977 | 10 (10) | <10 (<10) | <10 (<10) | 40 |
*
Serum samples from individuals ranging from 36 to 93 years of age.
†
Reciprocal dilution endpoint in VN titers.
‡
Reciprocal dilution in HI titration (in parentheses).