CYTOKINES OF THE HUMAN REPRODUCTIVE-TRACT

PROBLEM: How is it possible that the female genital tract immunologica lly does not reject spermatooa nor the preimplantation and nidating em bryo? METHODS: Four fluids of the human reproductive tract, i.e., huma n oviductal fluid (hOF), follicular fluid (FF), amniotic fluid (AF), a nd seminal plasma (SP) were investigated by specific ELISA for 18 cyto kines. The concentrations, presence or absence of these compounds were evaluated for their possible role in the immunology of the reproducti ve process. RESULTS: Stem cell factor and IL-11 were detected in all r eproductive tract fluids examined whereas large amounts of IL-1 beta a nd IL-1RA was found in AF and hOF. Follicular fluid revealed IL-2. HOF contained IL 2, IL-6, IL-8, TNF-alpha, MIP-1 alpha, IFN-gamma, and hi gh levels of IL-1 beta, IL-10, IL-1RA, and sIL-2R. Amniotic fluid cont ained sIL-2R, IL-8, IL-1 beta, IL-1RA, IL-6, TNF-alpha, and MIP-1 alph a. No IL-12 or IL-13 was detected in hOf, follicular fluid, or amnioti c fluid. Almost no free TGF-beta(1) or TGF-beta(2) was found in any re productive tract fluid except seminal plasma. Seminal plasma contained large quantities of free TGF-beta(1) (9,220 +/- 3,635 pg/mt) in addit ion to large quantities of latent TGF-beta(2) (2,933 +/- 2,169 pg/mL) and TGF-beta(1) (71,000 +/- 3,240 pg/mL). Furthermore, considerable co ncentrations of IL-8 (1900 +/- 374 pg/mL) and sIL-2R (350 mu/mL) exist in seminal plasma. CONCLUSIONS: HOF contains a high level of IL-10 (5 88 +/- 304 pg/mL), a powerful immune suppressor which probably plays a role in regulating immune responses in the fallopian tube and possibl y in the endometrial cavity. Our observations suggest that seminal pla sma with its huge content of TGF beta provides immune protection for s perm. Unfortunately, such high concentrations of TGF beta may also inh ibit an immune defense in any organ in which semen is deposited.