title: Primary human T-cell responses to the major outer membrane protein of Chlamydia trachomatis.
abstract: The major outer membrane protein (MOMP) of Chlamydia trachomatis is the main candidate antigen for a synthetic vaccine against chlamydial infection. Antibodies to surface-exposed epitopes on MOMP neutralize chlamydial infectivity but little is known about T-cell recognition of the molecule. We have measured primary human T-cell responses to recombinant fragments of MOMP as well as to the whole organism and synthetic MOMP peptides. Using antigen-pulsed low density cells (LDC) we were able to stimulate proliferative responses with T cells from most naive individuals. This response was antigen dose dependent and displayed an absolute requirement for dendritic cells in the antigen-presenting cell (APC) population. Several T-cell epitopes were identified in MOMP and one which stimulated T cells from 80% of donors was resolved as a 12 amino acid synthetic peptide. Dual cell surface labelling and cell cycle analysis by FACS revealed that both CD4+ and CD8+ T cells were stimulated in these cultures. The fact that we were able to obtain proliferative responses and interferon-gamma (IFN-gamma) production to MOMP using cells from cord bloods confirmed that these are genuine primary responses. These experiments have identified a region on MOMP, to which T cells from most humans make a primary response, which may be useful in a chlamydial vaccine. The approach is useful for vaccine development in general.
authors.affiliation: Antigen Presentation Research Group, Clinical Research Centre, Harrow, Middlesex, U.K.
authors.forename: A J
authors.initials: AJ
authors.lastname: Stagg
authors.forename: W A
authors.initials: WA
authors.lastname: Elsley
authors.forename: M A
authors.initials: MA
authors.lastname: Pickett
authors.forename: M E
authors.initials: ME
authors.lastname: Ward
authors.forename: S C
authors.initials: SC
authors.lastname: Knight
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016827:CD8 Antigens / Q000032:analysis; D002455:Cell Division / Q000276:immunology; D002692:Chlamydia trachomatis / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D005312:Fetal Blood / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D008969:Molecular Sequence Data; D018272:Porins; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D016827:CD8 Antigens; D018272:Porins; C071677:omp1 protein, Chlamydia trachomatis; D007371:Interferon-gamma