Lipid lesion areas in the aortic sinuses of the mice (and geometric means for the groups) inoculated with C. pneumoniae. Samples were taken at the age of 32 weeks. Group I, six inoculations, starting at the age of 8 weeks; group II, three inoculations, starting at the age of 8 weeks; group III, three inoculations, starting at the age of 20 weeks; group IV, three inoculations, starting at the age of 20 weeks, and cholesterol feeding started at 18 weeks; group V, uninfected control. One asterisk and two asterisks indicate significant differences compared with group I (P = 0.034 and P = 0.045, respectively). geom., geometric.