FIG 1.

Cross-reactivity of C. pneumoniae antibodies with the C. trachomatis OmcB ELISA. C. trachomatis OmcB ELISA was performed and IgG1 response was measured on adults (n = 85) who were C. trachomatis seronegative based on C. trachomatis EB ELISA and either C. pneumoniae seropositive (CP+ CT−) or C. pneumoniae seronegative (CP− CT−) based on C. pneumoniae EB ELISA (9). Data for OD₄₀₅ values are represented as a box-and-whiskers plot, with boxes denoting interquartile ranges and whiskers denoting the 5th and 95th percentiles. The median is shown as a horizontal line. Significance between the IgG1 responses was determined by the Wilcoxon rank sum test (ns, not significant).