Differential Regulation of CD4 Lymphocyte Recruitment between the Upper and Lower Regions of the Genital Tract during Chlamydia trachomatis Infection

ABSTRACT Genital infection with Chlamydia trachomatis results in both the local recruitment of protective immune responses and an inflammatory infiltrate that may also participate in tubal pathology. As a beginning to understanding the etiology of immune system-mediated tubal pathology, we evaluated the regional recruitment of lymphocyte subsets to different areas of the female genital tract (GT) over the course of a murine infection with the mouse pneumonitis agent ofChlamydia trachomatis (MoPn). Using flow cytometric techniques we found that the CD4 lymphocyte subset was preferentially recruited to the upper GT (oviduct and uterine horn) over the lower GT (cervical-vaginal region) throughout the course of MoPn infection. The influx of CD4 cells also correlated with the expression of endothelial cell adhesion molecules (ECAMs) and in vitro lymphocyte adherence in the upper GT. Interestingly, the expression of ECAMs in the lower GT was not maintained longer than 7 days after infection, even in the presence of viable chlamydiae. Taken together, these data suggest that regulatory mechanisms of lymphocyte recruitment differ between the upper and lower regions of the GT and may influence the clearance of chlamydiae and the development of tubal pathology.