Thèse de doctorat en Sciences médicales
Sous la direction de Jeanne Orfila.
Soutenue en 1995
à Compiègne .
Pas de résumé disponible.
Use of the polymerase chain reaction for the epidemiological and immunopathological study of chlamydia trachomatis infections
The Polymerase Chain Reaction technic was applied to the epidemiological and immunopathological study of Chlamydia trachomatis genital infections. Compared to a reference method combining cell culture and PCR, the PCR technic shows a sensitivity of 93. 6% and a specificity of 83. 8%, while cell culture presents a sensitivity of 47. 6% and a specificity of 98%. One hundred and seventy nine clinical isolates of C. Trachomatis were serotyped using the microimmunofluorescence method and genotyped by Restriction Fragment Length Polymorphism. One hundred and forty eight strains (82. 7%) gave similar results by the two technics, but 31 strains (17. 3%) gave discrepant results. These discrepancies are explained by a lack of specificity of the monoclonal antibodies. The epidemiological results obtained by RFLP are in agreement with the results observed in different countries at different time points. In order to find new epidemiological markers, we demonstrated the presence of repetitive extragenic palindromic sequences (REP) in C. Trachomatis chromosome. The Rep-PCR amplification pattern of C. Trachomatis differs from the amplification patterns of other bacteria. The PCR was used to detect cytokines mRNA in the genital tracts of mice infected with a human strain of C. Trachomatis. We detected an increase in the transcription of IL-1a, IL-1b, IL-2, IL-6, IL-10, IL-12, TNFa, IFNg and Macrophage Inflammatory Protein genes at D4 post-infection in infected mice compared to normal mice. Transcription rates of IL-2, IL-12 and IFNg remain high at D14 while the transcription rates of the other cytokines return to a baseline level. Therefore, C. Trachomatis infection seems to induce a Th1 immune response in vivo in a mouse model.