Age-dependent expression of immune-privilege and proliferation-related molecules on porcine Sertoli cells.

Background: The immunoprotective nature of the testes has prompted numerous investigations into their supportive roles during allogeneic or xenogeneic cellular grafts. However, the optimal developmental stage of these cells in terms of maximum efficacy for cellular grafts has not been elucidated. In this study, the time-dependent expressions of immune-privilege- and proliferation-related molecules in Sertoli cells were determined. Methods: To investigate the time course of the expression of proteins related to immune privilege and proliferation, immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) were performed using testes of 18 Yorkshire pigs from birth to 20 weeks of age. We included fas ligand (FasL), transforming growth factor beta 1 (TGF-beta 1) and clusterin as the immune-protective molecules, and follicle stimulating hormone receptor (FSHR), p27(Kip1), GATA-4 and Wilm's tumor antigen (WT1) as Sertoli cell proliferation markers. RT-PCR was used to complement histological assessment. Results: The expression of FasL in Sertoli cells gradually increased with age, whereas TGF-beta 1 showed the reverse pattern, and clusterin expression showed no age-related difference. p27(Kip1) showed a gradual increase in its expression from week 12, but GATA-4 showed earlier postnatal expression from birth to week 12. WT1 expression gradually increased from week 16. Conclusions: We confirmed the age-dependent expression of immune-privilege- and proliferation-related molecules in porcine Sertoli cells. These data may be useful for determining the optimal time for harvesting Sertoli cells with respect to maximal immunoprotection and proliferative activity.