Figure 5.

Quantification of capsular polysaccharide production by ELISA. Biological triplicate samples were processed in duplicate. Values for amount of capsule produced were interpolated from a standard curve of purified type-specific capsular polysaccharide (Statens Serum Institut, Denmark) and expressed as capsule produced per 1000 CFU (calculated from duplicate plating of each sample). Data are presented as the mean of biological replicates with error bars denoting the standard error of the mean. Significance was determined using a Kruskall–Wallis test by ranks followed by a Dunn's test between pairs. *p < 0.05. (a) Recombinant polysaccharide expression in E. coli: pB-4 values were an average of 115 pg ml⁻¹ (1000 CFU); pB-5 values were an average of 64 pg ml⁻¹ (1000 CFU); pB-8 values were an average of 44 pg ml⁻¹ (1000 CFU); and pB-12F values were an average of 104 pg ml⁻¹ (1000 CFU). (b) Polysaccharide expression from S. pneumoniae. SP 4 values were an average of 8 ng ml⁻¹ (1000 CFU); SP 5 values were an average of 3 ng ml⁻¹ (1000 CFU); SP 8 values were an average of 54 ng ml⁻¹ (1000 CFU); and SP 12F values were an average of 89 ng ml⁻¹ (1000 CFU).