Vaccination reduced histopathological lesions in indicated genital tracts following chlamydial challenge. Histopathology was assessed in naïve (uninfected/ healthy) and Chlamydia challenged CpG-, rCPAF/CpG-, CT-D-vaccinated guinea pigs. The genital tract of each guinea pig was removed at day 65 post CT-D challenge, sectioned, H&E stained, and analyzed microscopically (original magnification of the images is 100× or 200×). Histopathological injury in the genital tract of representative healthy and diseased guinea pigs was scored (a) and graphically represented for the respective group as a whole (b), for four distinct parameters (inflammatory cell infiltration, congestion, hemorrhage and edema). Obviously, the individual micrographs shown (a) represent the types of pathology observed in different regions of the genital tract of healthy and diseased animals, whereas the graph (b) summarizes these types of observations for all sections of all regions of all animals examined. The asterisk indicates significant reductions (* p <0.05; Kruskal-Wallis test with Dunns post hoc test) between CT-D or rCPAF/CpG immunized groups in comparison to CpG group for the respective parameters.