A primary Chlamydia trachomatis genital infection of Rhesus macaques identifies new immunodominant B-cell antigens

To identify immunodominant antigens that elicit a humoral immune response following a primary genital infection, rhesus monkeys were inoculated cervically with Chlamydia trachomatis serovar D. Serum samples were collected and probed with a protein microarray expressing 864/894 (96.4%) of the open reading frames of the C. trachomatis serovar D genome. The antibody response was analyzed in 72 serum samples from 12 inoculated monkeys. The following criteria were utilized to identify immunodominant antigens: proteins found to be recognized by at least 75% (9/12) of the infected monkeys with at least 15% elevations in normalized signal intensity from week 0 to week 8 post infection. All infected monkeys developed Chlamydia specific serum antibodies. Eight proteins satisfied the selection criteria for immunodominant antigens: CT242 (OmpH-like protein), CT541 (mip), CT681 (ompA), CT381 (artJ), CT443 (omcB), CT119 (incA), CT486 (fliY), and CT110 (groEL). Of these, three antigens, CT119, CT486 and CT381, were not previously identified as immunodominant antigens using non-human primate sera. In conclusion, these immunodominant antigens can now be tested for their ability to identify individuals with a primary C. trachomatis genital infection and to design a vaccine strategy to protect against a primary infection with this pathogen. A total of 15 rhesus monkeys were involved in tis Chlamydia trachomatis challenge study and a total of 72 sera from them were analyzed. Subjects were infected in the cervix with C. trachomatis serovar D and sera samples were taken throughout the course of infection. At baseline (week 0) 6 subjects received 10^7 IFU and 6 subjects received 10^5 IFU, and 3 subjects received SPG as controls. Sera samples were taken for all 15 subjects at weeks 0, 4, and 8. Samples were also taken at weeks 14, 18 and 23 for a subset of 9 of the subjects (7 of these 9 received 10^5 IFU at week 14).