T-cell epitopes in variable segments of Chlamydia trachomatis major outer membrane protein elicit serovar-specific immune responses in infected humans

We previously identified 18 stimulatory Chlamydia trachomatis major outer m embrane protein (MOMP) peptides containing at least 23 epitopes presented w ith various HLA class II allotypes, Only one peptide contained an epitope l ocalized in a variable segment (VS2), Continued studies reported here ident ified a total of five VS peptides containing T-cell epitopes that are distr ibuted among MOMPs VS1, VS2, and VS4, Only MOMP-primed T-cell cultures from subjects infected with serovar E responded to the serovar E VS peptides, w hile the response of such cultures to constant-segment peptides was indepen dent of the infecting serovar, Furthermore, MOMP-primed T cells proliferate d in response only to the VS peptides encoded in serovar E but not to the c orresponding peptides derived from serovar F, I, or J, confirming that thes e responses were serovar specific.