Intranasal administration of chlamydial outer protein N (CopN) induces protection against pulmonary Chlamydia pneumoniae infection in a mouse model

Vaccine. 2007 Jan 4;25(2):283-90. doi: 10.1016/j.vaccine.2006.07.043. Epub 2006 Aug 11.


Chlamydia pneumoniae is an intracellular pathogen that grows inside a vacuole, referred to as an inclusion. C. pneumoniae possess a type III secretion system (TTSS), which allows them to secrete effector molecules into the inclusion membrane and to the host cell cytosol. Proteins such as chlamydial outer protein N (CopN) that associate with the inclusion membrane are potential targets for the host's MHC-dependent antigen presentation, thereby representing ideal antigen candidates for T cell-based vaccination. The results of this study showed that intranasal immunization of BALB/c mice with heat-aggregated CopN protein and an Escherichia coli heat-labile toxin (LT) induced a strong immune response, detected as antigen-specific antibody production, lymphocyte proliferation and IFN-gamma production. Furthermore, the immunization induced statistically significant protection against intranasal C. pneumoniae challenge, the level of which correlated with the magnitude of CopN-specific lymphocyte proliferation. Both heat-aggregation of the antigen and the presence of LT adjuvant were required for maximal protective effect.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Intranasal
  • Animals
  • Antibodies, Bacterial / blood
  • Bacterial Proteins / immunology*
  • Bacterial Toxins / immunology
  • Bacterial Vaccines / administration & dosage*
  • Bacterial Vaccines / immunology
  • Chlamydia Infections / prevention & control*
  • Chlamydophila pneumoniae / immunology*
  • Disease Models, Animal
  • Enterotoxins / immunology
  • Escherichia coli Proteins / immunology
  • Immunization
  • Mice
  • Mice, Inbred BALB C
  • Pneumonia, Bacterial / prevention & control*


  • Antibodies, Bacterial
  • Bacterial Proteins
  • Bacterial Toxins
  • Bacterial Vaccines
  • Enterotoxins
  • Escherichia coli Proteins
  • heat-labile enterotoxin, E coli