Pneumococcal Capsular Polysaccharide Structure Predicts Serotype Prevalence
Figure 1
Effect of serotype on resistance to non-opsonic killing by neutrophils.
A) Capsule increases resistance of pneumococcus type 6B to non-opsonic surface killing compared to an unencapsulated derivative. Mean+/−SEM from a representative experiment. p<0.001 B) Capsule prevents association of pneumococcus type 6B with human PMNs. Mean+/−range from two independent experiments. MFI: Mean fluorescence intensity of neutrophils. C) Avoidance of neutrophil-mediated killing by the TIGR4 capsule variants is directly correlated with the frequency of each serotype among carriage isolates. Mean survival relative to serotype 9N is shown. ρ = 0.78, p<0.01. D) Susceptibility to neutrophil-mediated killing is a property of capsular type across diverse genetic backgrounds. Linear regression is shown comparing survival from neutrophil-mediated killing between isogenic TIGR4 capsule variants and diverse clinical isolates. Mean+/−range., ρ = 0.49, p<0.05.