Immunization With the Attenuated Plasmidless Chlamydia Trachomatis L2(25667R) Strain Provides Partial Protection in a Murine Model of Female Genitourinary Tract Infection

Vaccine. 2010 Feb 10;28(6):1454-62. doi: 10.1016/j.vaccine.2009.11.073. Epub 2009 Dec 8.


Here we report on the safety, immunogenicity, and vaccine efficacy of the naturally occurring plasmid-free attenuated Chlamydia trachomatis L2-25667R (L2R) strain in a murine infection model. Intravaginal immunization induced both chlamydial specific serum antibody and systemic CD4(+) Th1 biased immune responses but failed to induce local IgA antibodies. Immunization induced no pathological changes in the urogenital tract. Protective immunity was evaluated by vaginal challenge with a natural occurring non-attenuated plasmid positive C. trachomatis urogenital strain (serovar D). Vaccinated mice were not protected from colonization/infection but exhibited a reduction in infectious burden at early time periods (1-2 weeks) post-challenge. Partial protective immunity did not protect against inflammatory disease. Thus, intravaginal vaccination with the live-attenuated L2R stain is safe, induces a systemic antibody and CD4(+) Th1 biased immune response, but its protective efficacy is limited to reducing chlamydial burden at early time periods post-infection.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Administration, Intravaginal
  • Animals
  • Antibodies, Bacterial / blood
  • Bacterial Vaccines / administration & dosage
  • Bacterial Vaccines / adverse effects
  • Bacterial Vaccines / genetics
  • Bacterial Vaccines / immunology*
  • CD4-Positive T-Lymphocytes / immunology
  • Chlamydia trachomatis / genetics
  • Chlamydia trachomatis / immunology*
  • Colony Count, Microbial
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Genitalia, Female / microbiology
  • Genitalia, Female / pathology
  • Histocytochemistry
  • Immunoglobulin A / blood
  • Immunoglobulin G / blood
  • Immunohistochemistry
  • Lymphogranuloma Venereum / immunology
  • Lymphogranuloma Venereum / microbiology
  • Lymphogranuloma Venereum / prevention & control*
  • Mice
  • Mice, Inbred C3H
  • Microscopy
  • Plasmids
  • Vaccines, Attenuated / administration & dosage
  • Vaccines, Attenuated / adverse effects
  • Vaccines, Attenuated / genetics
  • Vaccines, Attenuated / immunology


  • Antibodies, Bacterial
  • Bacterial Vaccines
  • Immunoglobulin A
  • Immunoglobulin G
  • Vaccines, Attenuated