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Updated: Apr 26, 2026
Isolation of Lymphocytes from Mouse Genital Tract Mucosa
Published on: September 3, 2012
Protection promoted by pGP3 or pGP4 against Chlamydia muridarum is mediated by CD4(+) cells in C57BL/6N mice
Tímea Mosolygó1, Agnes M Szabó1, Emese P Balogh1
1Department of Medical Microbiology and Immunobiology, University of Szeged, Szeged, Hungary.
Abstract:
Urogenital tract infection with Chlamydia trachomatis is a leading cause of sexually transmitted infections. There is currently no commercially available vaccine against C. trachomatis. The highly conserved plasmid of chlamydiae has been considered to be a virulence factor and the plasmid proteins have important roles in the Chlamydia-specific immune response. This study was designed to evaluate the efficacy of vaccination with plasmid proteins in the prevention of C. muridarum lung infection in a mouse model. C57BL/6N mice were immunised 3 times subcutaneously with recombinant pGP3 or pGP4 and infected with C. muridarum. Immunisation of the mice with recombinant pGP3 or pGP4 protein caused a significantly lower chlamydial burden in the lungs of the infected mice; the lower IFN-γ level indicated a reduced extent of inflammation. In vitro or in vivo neutralisation of C. muridarum with sera obtained from immunised mice did not reduce the number of viable C. muridarum in the lungs of mice. However, adoptive transfer of the CD4(+) spleen cells isolated from the immunised mice resulted in a significantly reduced bacterial burden. Our results indicate that it is not the pGP3- and pGP4-specific antibodies, but the CD4(+) cells that are responsible for the protective effect of the immune response to plasmid proteins.
Insights
Vaccinating mice with Chlamydia trachomatis plasmid proteins, pGP3 and pGP4, reduced lung infection burden. Protective immunity was mediated by CD4(+) T cells, not antibodies, highlighting a novel vaccine target.
Area of Science:
- Immunology
- Microbiology
- Vaccinology
Background:
- Chlamydia trachomatis causes widespread sexually transmitted infections, with no current vaccine.
- Chlamydial plasmids and their proteins are crucial for virulence and host immune responses.
- Developing effective vaccines against Chlamydia remains a significant public health challenge.
Purpose of the Study:
- To assess the efficacy of vaccination using Chlamydia plasmid proteins (pGP3, pGP4) against C. muridarum lung infection in a mouse model.
- To elucidate the immune mechanisms underlying protection induced by plasmid protein vaccination.
Main Methods:
- C57BL/6N mice were subcutaneously immunized three times with recombinant pGP3 or pGP4 proteins.
- Mice were subsequently infected with C. muridarum to evaluate lung chlamydial burden and inflammation (IFN-γ levels).
- In vitro and in vivo neutralization assays using sera, and adoptive transfer of CD4(+) spleen cells from immunized mice were performed.
Main Results:
- Immunization with pGP3 or pGP4 significantly reduced chlamydial lung burden and inflammation.
- Sera from immunized mice did not neutralize C. muridarum in vitro or in vivo.
- Adoptive transfer of CD4(+) spleen cells from immunized mice conferred significant protection against lung infection.
Conclusions:
- Vaccination with Chlamydia plasmid proteins pGP3 and pGP4 induces protective immunity against C. muridarum lung infection.
- The protective effect is primarily mediated by CD4(+) T cells, rather than antibodies.
- These findings suggest CD4(+) T cell induction as a key strategy for developing Chlamydia vaccines.
