title: Immunization with the attenuated plasmidless Chlamydia trachomatis L2(25667R) strain provides partial protection in a murine model of female genitourinary tract infection.
abstract: 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.
authors.affiliation: Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, NIAID, NIH, 903 S 4th Street, Hamilton, MT 59840, USA.
authors.forename: Norma
authors.initials: N
authors.lastname: Olivares-Zavaleta
authors.forename: William
authors.initials: W
authors.lastname: Whitmire
authors.forename: Donald
authors.initials: D
authors.lastname: Gardner
authors.forename: Harlan D
authors.initials: HD
authors.lastname: Caldwell
mesh_terms: D000282:Administration, Intravaginal; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000009:adverse effects / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002692:Chlamydia trachomatis / Q000235:genetics / Q000276:immunology*; D015169:Colony Count, Microbial; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005836:Genitalia, Female / Q000382:microbiology / Q000473:pathology; D006651:Histocytochemistry; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007150:Immunohistochemistry; D008219:Lymphogranuloma Venereum / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D051379:Mice; D008809:Mice, Inbred C3H; D008853:Microscopy; D010957:Plasmids; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000009:adverse effects / Q000235:genetics / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D014613:Vaccines, Attenuated