2C & 2D). of the upper reproductive tract to HIV-1 infection. Keywords:T-cell, CTL, HIV, STD, Endometrium, Endocervix == INTRODUCTION == The female reproductive tract (FRT) is unique in that it must be immunologically tolerant of a semi-allogeneic conceptus, but must also retain the ability to respond to potential pathogens. The lower FRT includes the vagina and ectocervix; the upper FRT includes the endocervix, uterine endometrium and fallopian tubes. The mucosal lining in the lower FRT is composed of multi-layered stratified squamous epithelium1, whereas the upper FRT is lined by single-layered columnar epithelium with tight junctions2,3. The mucosal immune system in the FRT consists of epithelial cells, stromal cells and immune cells that migrate into the uterus, cervix and vagina4and provide a robust physical and immunological barrier against sexually transmitted infections5. Epithelial cells of the FRT express toll-like receptors6as well as intracellular pattern recognition receptors7and secrete a variety of cytokines, growth factors, chemokines and antimicrobial peptides that participate in host defense through interactions with immune cells that reside in the epithelium and the stromal layer8,9. Lymphocytes and antigen presenting cells are present throughout the FRT. Leukocytes comprise 620% of total cells and are dispersed throughout the FRT tissues with the highest proportion seen in the uterine endometrium and fallopian tubes10. The major population of leukocytes consists of T-lymphocytes, including CD3+ lymphocytes. Granulocytes are also present, particularly in the fallopian tubes. B-lymphocytes and monocytes are dispersed throughout the FRT, but are not as prominent as T-lymphocytes and granulocytes11. In the upper FRT, reproductive hormone levels modulate immune functions including cytotoxic T lymphocyte (CTL) activity, secretion of immunoglobulins, cytokines, chemokines, growth factors and antimicrobial peptides over the course of the menstrual cycle1115. In contrast to the upper FRT, CTL activity and the frequency and distribution of immune cells in the lower FRT (i.e., ectocervix and vagina) remain constant throughout the menstrual cycle1517. Previous studies suggest that the upper FRT might also be a portal for the entry of HIV-1 following sexual intercourse5,1820. Susceptibility of the upper tract to infection likely varies throughout the menstrual cycle, with the highest susceptibility predicted at mid-luteal phase5,9,2124. Here, we have studied the phenotype and functionality of fresh CD4+ and CD8+ T cells isolated from the endometrium, endocervix, and peripheral blood (PB), collected from healthy premenopausal women during the mid-luteal (secretory) phase of the menstrual cycle. T-cells of both endocervix and endometrium had a predominant activated, effector memory phenotype with increased expression of CCR5 as compared to blood T-cells. Notably, mid-luteal endometrial CD4+ T-cells were significantly enriched for a CCR5+, activated, effector memory phenotype as compared to their counterparts in endocervix, suggesting high susceptibility to HIV-1 infection. In addition, endometrial T-cells (both CD4+ and CD8+) were more responsive to polyclonal stimuli, producing pro-inflammatory cytokines and chemokines, compared to blood T-cells. Taken together, these results reveal that endometrial T-cells have a phenotype that may render them highly susceptible to infection by HIV-1 and other sexually transmitted pathogens. == MATERIALS AND METHODS == == Study participants and PRX-08066 specimen collection == Participants were enrolled in two clinical research studies approved by University NOX1 of California, San Francisco (UCSF) Committee on Human Research (CHR). The exclusion criteria for both studies were pregnancy, a current genital herpes outbreak or 4 or more herpes outbreaks in the last year, PRX-08066 irregular menses, an abnormal Pap test within the past 12 months, recent use of intravaginal or intrauterine contraceptives, use of exogenous sex hormones, PRX-08066 abnormal vaginal discharge or bleeding, immunocompromised status or use of immunosuppressive medications, or daily use of nonsteroidal anti-inflammatory drugs. Within 711 days post luteinizing hormone surge during the mid-luteal phase approximately 20 mL of PB were collected in vacutainer tubes coated with EDTA (BD Pharmingen, SA Jose, CA) and endometrial biopsies were.
2C & 2D)
