Identification of CT521 as a Frequent Target of Th1 Cells in Patients with Urogenital Chlamydia trachomatis Infection

• Published in: The Journal of infectious diseases 2006-11, Vol.194 (9), p.1258-1266
• Main Authors: Olsen, Anja Weinreich, Follmann, Frank, Jensen, Klaus, Højrup, Peter, Leah, Robert, Sørensen, Hanne, Hoffmann, Steen, Andersen, Peter, Theisen, Michael
• Format: Article
• Language: English
• Subjects: Adult; Antigens; Antigens, Bacterial - immunology; Bacteria; Bacterial diseases; Bacterial diseases of the urinary system; Bacteriology; Biological and medical sciences; Chlamydia; Chlamydia Infections - immunology; Chlamydia trachomatis; Chlamydia trachomatis - immunology; Epitopes; Epitopes, T-Lymphocyte - immunology; Female; Female Urogenital Diseases - microbiology; Fundamental and applied biological sciences. Psychology; Gels; Genitalia; Human bacterial diseases; Humans; Infections; Infectious diseases; Interferons; Male; Male Urogenital Diseases - microbiology; Medical sciences; Membrane proteins; Microbiology; Miscellaneous; T lymphocytes; Th1 Cells - physiology
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1086/508203

BackgroundThe human immune response to a Chlamydia trachomatis serovar D lysate was investigated in patients with urogenital C. trachomatis infection, to identify novel T cell targets MethodsA C. trachomatis lysate was fractionated on the basis of molecular mass, and each fraction was used to stimulate peripheral-blood mononuclear cells from patients with C. trachomatis infection. In frequently recognized fractions, proteins were identified by mass spectrometry, recombinantly expressed, and tested for T cell recognition ResultsT cell recognition of the fractions was highly heterogeneous in patients with C. trachomatis infection (n=16). Four patients exhibited responses that were strongly targeted to antigens of 16–20-kDa molecular mass. Three proteins were identified in this fraction: CT043, CT511, and CT521. The T cell response to the individual recombinant proteins were investigated, and CT521 was found to induce the highest level of interferon (IFN)–γ. The recognition of CT521 was investigated in a larger study population (n=41), and a positive IFN-γ response was measured in 83% of the patients. Several T cell epitopes were identified in CT521; in particular, peptide 5 in the central part of the protein was frequently recognized by T cells (63%) ConclusionWe have identified a novel C. trachomatis antigen, CT521, that is frequently recognized in patients with urogenital C. trachomatis infection