Fig. 1.

Effect of pneumococcal strains of different serotypes on CXCL8 induction in human nasopharyngeal epithelial cells. Detroit 562 nasopharyngeal epithelial cells were assessed for CXCL8 release after exposure to wildtype (a) or capsule switch mutant (b) pneumococcal strains. a Strain 207.31 induced more CXCL8 than either strain 103.57 or strain 208.41 but there were no other significant differences in CXCL8 induction between the clinical isolates. b No significant differences in CXCL8 induction were detected between any of the strains of different serotypes but the same genetic background. All experiments were performed in triplicate. Serotypes are indicated in brackets, NT refers to the nontypeable capsule deletion mutant. Negative control refers to Detroit cells in the absence of bacteria. * indicates significant difference by ANOVA with Tukey’s post hoc test. Error bars indicate standard deviation