keratinizing barrier epithelial cell keratinocyte An epithelial cell of stratified squamous tissues, including skin, oral mucosa (Hiroshima et al., 2011), and esophagus (Whelan et al., 2018), that produces keratin proteins and secretes antimicrobial peptides to form a resilient barrier against environmental damage, dehydration, pathogens, and microbial invasion. It undergoes successive stages of differentiation marked by changes in keratin expression, supporting tissue integrity, wound repair, and contributing to immune defense. FMA:62879 CALOHA:TS-0500 ZFA:0009158 BTO:0000667 Homo sapiens