Differential regulation of CD4 lymphocyte recruitment between the upper and lower regions of the genital tract during Chlamydia trachomatis infection

Genital infection with Chlamydia trachomatis results in both the local recr uitment of protective immune responses and an inflammatory infiltrate that may also participate in tubal pathology. As a beginning to understanding th e etiology of immune system-mediated tubal pathology, we evaluated the regi onal recruitment of lymphocyte subsets to different areas of the female gen ital tract (GT) over the course of a murine infection with the mouse pneumo nitis agent of Chlamydia trachomatis (MoPn). Using flow cytometric techniqu es 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 a lso correlated with the expression of endothelial cell adhesion molecules ( ECAMs) and in vitro lymphocyte adherence in the upper GT. Interestingly, th e 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 d iffer between the upper and lower regions of the GT and may influence the c learance of chlamydiae and the development of tubal pathology.