Mucosal and Systemic Immune Responses to Plasmid Protein pgp3 in Patients With Genital and Ocular Chlamydia Trachomatis Infection

Clin Exp Immunol. 2003 Jun;132(3):436-42. doi: 10.1046/j.1365-2249.2003.02163.x.


The circulating and cervical B cell responses to Chlamydia trachomatis plasmid protein pgp3 were characterized in children and adults with ocular or genital chlamydial infection using the enzyme-linked immunospot assay (ELISPOT) and ELISA. No pgp3-specific ASCs were detected in healthy controls, but predominantly IgA ASCs were detected in UK adults with uncomplicated cervicitis or urethritis (P = 0.03, 0.019). In patients with extragenital complications or pelvic inflammatory disease a mixed response with more IgG and IgM ASCs was evident, suggesting a breach of mucosal immune compartmentalization with more extensive infection. In women with chlamydial cervicitis, ASCs secreting predominantly IgA, but also IgG, to pgp3 were present in cervix at presentation, with a frequency 30-50 times higher than blood. Cervical ASC numbers, especially IgG, fell markedly six weeks after antibiotic treatment. We detected principally IgA pgp3-specific antibody secreting cells (ASCs) in children resident in a Gambian endemic area, with a trend towards suppression of IgA responses during intense trachomatous inflammation (P = 0.06), as previously reported for other chlamydial antigens, and in keeping with the findings in genital disease. These data provide a rationale for further studies of immune responses to pgp3 in humans and animal models of chlamydia-induced disease, and its potential use in diagnostic assays and protective immunization strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-Bacterial Agents / therapeutic use
  • Antibodies, Bacterial / biosynthesis
  • Antibody Specificity
  • Antibody-Producing Cells / immunology
  • Antigens, Bacterial / immunology*
  • Bacterial Proteins / immunology*
  • Child
  • Chlamydia Infections / drug therapy
  • Chlamydia Infections / immunology*
  • Chlamydia trachomatis / immunology*
  • Enzyme-Linked Immunosorbent Assay / methods
  • Female
  • Humans
  • Immunity, Mucosal
  • Immunoglobulin A / biosynthesis
  • Immunoglobulin G / biosynthesis
  • Immunoglobulin M / biosynthesis
  • Male
  • Trachoma / immunology*
  • Trachoma / microbiology
  • Urethritis / immunology
  • Urethritis / microbiology
  • Uterine Cervicitis / drug therapy
  • Uterine Cervicitis / immunology*
  • Uterine Cervicitis / microbiology


  • Anti-Bacterial Agents
  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Bacterial Proteins
  • Immunoglobulin A
  • Immunoglobulin G
  • Immunoglobulin M
  • pgp3 protein, Chlamydia