This contract will study T cell epitopes in sexually transmitted infection (STI) pathogens: herpes simplex virus types 1 and 2, Treponema pallidum (Tp, syphilis), and Chlamydia trachomatis (Ct). The Deliverables are validated “pairs” of 1) microbial peptide epitopes, and 2) restricting HLA alleles. For HSV, we Offer “triads” that, in addition, also include 3) paired TCRαβ recognizing HSV peptide-HLA complexes. The Approaches enrich STI pathogen-specific T cells from blood or relevant tissues of cohorts of STI pathogen-infected humans.