TABLE 2.
Proportions of sera with cross-reactivity of antibody binding to type 6B, 14, 19F, and 23F PSs
| Sera | Proportion (%) of sera with cross-reactivitya to:
|
|||
|---|---|---|---|---|
| 6B | 14 | 19F | 23F | |
| Nonimmunized | ||||
| Adult prevaccination serab | 11/14 (79) | 0/14 (0) | 10/14 (71) | 7/12 (58) |
| Sera from nonimmunized infants (6, 7, 14 mo) | 4/6 (67) | 0/6 (0) | 4/6 (67) | 4/6 (67) |
| Immunized | ||||
| Adult postvaccination serac | 4/17 (24) | 0/17 (0) | 4/17 (24) | 2/17 (12) |
| Sera from immunized infants (7 mo)d | 0/12 (0) | 0/11 (0) | 0/12 (0) | 0/11 (0) |
a
Cross-reactivity (≥50% reduction in OD) was tested with sera from adults and infants, both nonimmunized and immunized. For the various Pnc PS types, the number of sera used in the inhibition experiments differed, as indicated, because only sera that had enough antibodies to the specified Pnc PS were suitable.
b
Sera obtained before (day zero) immunization with either PS vaccine or PncD conjugate.
c
Sera obtained 28 days after immunization with either PS vaccine or PncD conjugate.
d
Sera obtained from 7-month-old infants who had been immunized with PncD conjugate at 2, 4, and 6 months.