Expression of fractalkine in the Fallopian tube and of CX3CR1 in sperm.

BACKGROUND Fractalkine is a CX(3)C chemokine that has chemoattractant activity for T cells, monocytes and natural killer (NK) cells. The objective of this study was 2-fold: to evaluate (i) the presence of fractalkine in the Fallopian tube and (ii) the existence of CX(3)CR1 (fractalkine receptor) in ejaculated sperm. METHODS AND RESULTS Western blot analysis revealed that fractalkine protein was detected as a 95 kDa band in the isthmus, the ampulla and the infundibulum of the Fallopian tube. Immunohistochemistry revealed positive staining of epithelial cells in the Fallopian tube. RT-PCR demonstrated that fractalkine transcripts were expressed in all parts of the Fallopian tube. RT-PCR also revealed that CX(3)CR1-positive cells were present in the Fallopian tube. CX(3)CR1-positive cells were present in the stroma of the Fallopian tube. The villi of the ciliated cells were positively stained. To determine the function of fractalkine in the Fallopian tube, we examined whether CX(3)CR1 was present in ejaculated sperm. RT-PCR demonstrated that CX(3)CR1 transcripts were expressed in the ejaculated sperm. Immunohistochemistry demonstrated positive staining of the tail of the spermatozoa. CONCLUSIONS The present findings suggest that fractalkine in the Fallopian tube contributes to the immunodefence mechanism during fertilization and to the sperm motion in the oviduct.