ABSTRACT: In mice, seminal fluid elicits an inflammation-like response in the female genital tract that activates immune adaptations to advance the likelihood of conception and pregnancy. Here we examined whether similar changes in leukocyte and cytokine parameters occur in the human cervix in response to the male partner’s seminal fluid. After a period of abstinence in proven-fertile women, duplicate sets of biopsies were taken from the ectocervix in the peri-ovulatory period and again 48 h later, 12 h after unprotected vaginal coitus, vaginal coitus with use of a condom, or no coitus. One pair of first biopsy and second biopsy RNA samples from each treatment group were reverse transcribed into cDNA and hybridized to Affymetrix Human Gene 1.0 ST arrays. A total of 713 probe sets were identified as differentially expressed (fold change >2) between first and second biopsies after unprotected coitus, with 436 genes upregulated and 277 genes downregulated. Ingenuity Pathway Analysis revealed that gene pathways including inflammatory response, immune response, immune cell trafficking, cellular movement and antigen presentation were significantly affected by seminal fluid exposure. Amongst these were genes encoding several chemokines which target granulocytes, monocyte/macrophages, dendritic cells and lymphocytes, proinflammatory cytokines and regulators of cytokine synthesis, prostaglandin pathway gene including PTGS2; COX-2) and several matrix metalloproteinases (MMPs). Of these genes, no change or a substantially smaller change was seen between first and second biopsies obtained after coitus with condom use, or abstinence. An increase in CSF2, IL6, IL8 and IL1A expression was confirmed by qRT-PCR in larger sets of duplicate biopsies (n=6-7 per group). We conclude that seminal fluid introduced at intercourse elicits expression of pro-inflammatory cytokines and chemokines which underpins the accompanying recruitment of macrophages, dendritic cells and memory T cells. The leukocyte and cytokine environment induced in the cervix by seminal fluid appears competent to initiate adaptations in the female immune response that promote fertility. This response is also relevant to transmission of sexually transmitted pathogens, and potentially susceptibility to cervical metaplasia. Women aged 18-40 years, with regular menstrual cycles and a current sexual relationship with a proven fertile regular partner, volunteered for the study. All women had previously undergone tubal ligation and none of the women used steroidal contraceptives or an intrauterine device for a minimum of three months preceding the study. Subjects were screened to exclude bacterial or viral infection. A negative test result was a prerequisite for inclusion in the study. The study was approved by the local ethics committee of Karolinska University Hospital, Stockholm, Sweden. RNA from each of six cervical biopsies was analysed. The six tissues comprised three pairs of cervical biopsies (a ‘first’ and a ‘second’ biopsy); one pair from each of three women assigned to three different treatment protocols. Treatments were (1) no coitus (control); (2) coitus with a condom (condom), or (3) unprotected coitus (coitus). To synchronise the timing of the biopsies, all subjects determined their LH peak in urine samples taken twice daily from approximately day 10 after the onset of menstruation to the time at which an LH increase was detected (LH0-LH+1), using a rapid self-test (Clearplan, Searle Unipath Ltd., Bedford, UK). The first biopsy was recovered during the peri-ovulatory stage of the menstrual cycle (at 0900 h - 1200 h on day LH0 to LH+1), and the second biopsy was recovered 48 h later (at 0900 h - 1200 h on day LH+2 to LH+3). Small needle biopsies (approximately 50-100 mg tissue) were taken from the ectocervix, approximately 1 cm from the transformation zone. Women then abstained from intercourse for 36 hours to enable haemostasis and healing of the biopsy site. Women allocated to groups (1) and (2) had intercourse, without or with condom use respectively, on one occasion approximately 36 hours after the first biopsy and 12 hours prior to the second biopsy. The abstinent woman did not have intercourse between the two biopsies. Before all biopsies, the cervix was washed with 10 ml of saline solution to clear mucous and debris. All cervical washings were collected and examined microscopically for the presence of sperm to confirm compliance.
