Establishment and Characterization of an Immortalized Oviduct Epithelial Cell Line from Yak (Bos grunniens)

Oviduct epithelial cells (OECs) constitute a critical component of the oviductal mucosa, providing essential microenvironmental support for fertilization and early embryonic development. Their frequent application in embryo co-culture systems is constrained in yaks (<i>Bos grunniens</i>) by limited tissue availability and the short lifespan of primary yak oviduct epithelial cells (YOECs). To address this limitation, we established immortalized YOEC lines using a lentiviral vector system. Primary YOECs isolated from reproductive tract tissues of adult female yaks via enzymatic digestion were immortalized through individual and combined transfection with simian virus 40 large T antigen (SV40LT) and human telomerase reverse transcriptase (hTERT). The resulting immortalized lines (YOECs-S: SV40LT alone; YOECs-HS: dual SV40LT/hTERT) kept their typical cobblestone shape and still made cytokeratin 18. Both lines exhibited stable SV40LT and hTERT expression (<i>p</i> > 50), maintained diploid karyotypes, and demonstrated serum-dependent growth, contact inhibition, and hormone responsiveness. Notably, YOECs-HS displayed superior proliferative capacity and phenotypic stability during long-term culture. This study reports the first successful establishment and comprehensive characterization of immortalized YOEC lines. These validated models provide a valuable experimental platform for optimizing yak embryo-oviduct epithelial cell co-culture systems and advancing reproductive research in this high-altitude-adapted species.