Oral keratinocytes act as the major barrier to physical, microbial, and chemical agents that may cause local cell injury. They are involved in the proinflammatory process through the production of cytokines either constitutively or after a variety of stimuli. Consequently, oral keratinocytes may potentially participate in controlling oral infections through an inflammatory process involving different interleukins, such as IL-1β and IL-18. Oral keratinocytes express a variety of differentiation markers, the expression of which is influenced by calcium-induced changes in the transcription of target genes. Oral keratinocytes share major structural and functional features with the well-characterized dermal keratinocyte and are a good model to study basic keratinocyte biology, as well as, processes of immortalization and malignant transformation. HOK from ScienCell Research Laboratories are isolated from human oral mucosa. HOK are cryopreserved at passage one and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HOK are characterized by immunofluorescence with antibodies specific to cytokeratin-18 and/or cytokeratin-19. HOK are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HOK are guaranteed to further expand for 10 population doublings under the conditions provided by ScienCell Research Laboratories. Recommended Medium It is recommended to use Oral Keratinocyte Medium (OKM, Cat. No. 2611) for the culturing of HOK in vitro.