Sperm modulate uterine immune parameters relevant to embryo implantation and reproductive success

Seminal fluid factors modulate the female immune response at conception to facilitate embryo implantation and reproductive success. Whether sperm affect this response has not been clear. We evaluated global gene expression by microarray in the mouse uterus after mating with intact or vasectomized males. Intact males induced greater changes in gene transcription, prominently affecting pro-inflammatory cytokine and immune regulatory genes, with TLR4 signaling identified as a top-ranked upstream driver. Recruitment of neutrophils and expansion of peripheral regulatory T cells were elevated by seminal fluid of intact males. In vitro, epididymal sperm induced IL6, CXCL2, and CSF3 in uterine epithelial cells of wild-type, but not Tlr4 null females. Collectively these experiments show that sperm assist in promoting female immune tolerance by eliciting uterine cytokine expression through TLR4-dependent signaling. The findings indicate a biological role for sperm beyond oocyte fertilization, in modulating immune mechanisms involved in female control of reproductive investment. We used microarrays to detail the global programme of gene expression in mice following exposure to different components of seminal fluid CBAF1 females mated with intact or vasectomized BALB/c males were euthanized at 8 h post mating, or at 2000 h on the day of pro-estrus for unmated controls, and uterine tissue was harvested. Uterine endometrium was recovered and processed for microarray. Endometrial RNA from n=16 females was pooled into four independent biological replicates per treatment group (4 x control, 4 x intact, 4 x vasectomized) and analyzed using Affymetrix Mouse Gene 1.0 ST Arrays (Affymetrix, Santa Clara CA)