Influence of Chlamydia trachomatis Sequence Variation on pgp3 Antigenicity.

Chlamydia trachomatis (Ct) is a sexually transmitted infection (STI) linked to ectopic pregnancy, infertility, invasive lymphogranuloma venereum (LGV), and the blinding disease trachoma. STI, LGV, and trachoma are associated with disease-specific Ct genovars. Serology is an important surveillance tool for estimating exposure, but the impact of genome variation on the antigenicity of Ct proteins is unclear. Two-dimensional antigenicity profiling of Pgp3 antigens representing LGV, STI, and trachoma demonstrated differential antigenicity using antigen-specific murine sera, but geometric distances were not considered significant (≤2-fold) for human infection sera. Pgp3 should be considered a single serotype for the purposes of Ct serosurveillance.