Antigen-Specific Cell Mediated Immune Response to Chlamydia Trachomatis
Condition: Chlamydia
MeSH terms: Chlamydia Infections
Study type: Observational

Summary: 
      This is an exploratory study in which the investigators will develop a way to identify the
      cell responses most strongly associated with protection against chlamydia infection. This
      study is not driven by a hypothesis.
    

Detailed description: 
      With more than 90 million new cases annually, Chlamydia trachomatis is the most common
      sexually transmitted bacterial disease. Untreated endocervical C. trachomatis infections can
      cause pelvic inflammatory disease (PID), a disorder of the endometrium, fallopian tubes, and
      adjacent structures that occurs after ascension of the bacterium from the lower to upper
      genital tract. Adverse outcomes secondary to C. trachomatis-induced PID include tubal
      infertility, ectopic pregnancy, and chronic pelvic pain. Vaccine development has been
      identified as essential for control of C. trachomatis infections, and current evidence
      suggests that an effective vaccine will likely be based on several C. trachomatis antigens.
      Experimental models of infection have identified HSP60, major outer-membrane protein (MOMP),
      outer membrane protein 2 (OMP2), and polymorphic membrane protein D (PmpD) as promising
      vaccine candidates. A prospective study of Kenyan commercial sex workers found that
      production of interferon-gamma (IFN-γ) by peripheral blood cells stimulated with chlamydia
      heat-shock protein (HSP60) strongly correlated with protection against incident C.
      trachomatis infection. This proposal details an exploratory identification of the
      antigen-specific cell mediated immune responses associated with antecedent C. trachomatis
      infection in women.

      C. trachomatis is an obligate, intracellular, gram-negative microorganism recognized as the
      most common bacterial sexually transmitted disease worldwide. The highest rates of infection
      with this organism are consistently found among adolescents and young adults. Young women are
      also the group most adversely impacted by the effects of C. trachomatis infection on
      reproductive health. While approximately 70% of infections with C. trachomatis in young women
      are asymptomatic, 20% - 40% of these occult infections will progress from endocervical
      inflammation to the development of PID. In addition to its strong association with PID, C.
      trachomatis infection is also thought to enhance HIV transmission and contribute to human
      papilloma virus induced cervical neoplasia. Although data from both experimental models and
      clinical studies suggest that antigen specific CD4+ and CD8+ T cells are required for optimal
      control of genital tract chlamydial infections, the current lack of information regarding the
      specific C. trachomatis antigens eliciting protective immune responses in humans hinders
      vaccine development.

      This is an exploratory investigation in which we will develop the methodology needed to
      identify the antigen-specific cell mediated immune responses most strongly associated with
      protection against incident C. trachomatis infection.
    

Observational model: Case-Only
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        20 women with history of endocervical chlamydia and 10 women with no history of
        endocervical chlamydia
      
Keywords: chlamydia; healthy women; history of endocervical chlamydia; no history of endocervical chlamydia