TABLE 3.
Capsular polysaccharide content of S. pneumoniae type 3 (ATCC 6303 and WU2) and type 3 mutant strains (JY1123 and DW3.8) before and after trypsin treatment
| Pneumococcal strain | PS3 content (fg/bacterium) after pretreatmenta:
|
|
|---|---|---|
| None (VSB++) | Trypsin | |
| ATCC 6303 (Caps+/PspA+) | 17.2 ± 3.2 | 34.7 ± 6.2 |
| WU2 (Caps+/PspA+) | 124 ± 14.5 | 213 ± 27.6 |
| JY1123 (Caps+/PspA−) | 149 ± 29.4 | 156 ± 27.6 |
| DW 3.8 (Caps−/PspA−) | <0.004b | <0.004b |
a
The type 3 capsular polysaccharide content (PS3) was measured by ELISA and is expressed as femtograms per bacterial cell (see Materials and methods).
b
Below detection limit (means ± standard errors of three separate experiments).