ACTIVATION OF LATENT TRANSFORMING GROWTH-FACTOR-BETA DURING CHLAMYDIATRACHOMATIS-INDUCED MURINE PNEUMONIA

Transforming growth factor beta (TGF beta) is a multifunctional cytoki ne with potentially important roles in both host defence and immunopat hogenesis. Latent, but more importantly, active TGF beta was significa ntly elevated in bronchiolar lavage fluid from lungs of mice infected with murine Chlamydia trachomatis. Induction of both latent and active TGF beta in these infected animals was highest at day two after infec tion (2 to 4-fold) compared with day 15 (1 to 2-fold). Both active and latent TGF beta 1 and TGF beta 2 isoforms were detected. Quantitative reverse transcription polymerase chain reaction (RT-PCR) assay showed a slight but significant increase in PCR product for TGF beta 1, but Northern analysis for TGF beta 1 in lung tissue was not significantly different between treatment groups. No significant change was observed for TGF beta 2 mRNA by RT-PCR. The increase in active and latent TGF beta in these lung lavages from mice infected with C. trachomatis appe ars to be primarily post-transcriptionally regulated.