<2100>人表皮角质细胞（HEK-n）-新生和<2110>人表皮角质细胞（HEK-a）-成人分别提取于新生儿和成人的表皮组织，于原代冻存。
 
    皮肤上皮层是一层保护机体免受外界环境损伤的重要屏障。该层主要为角质细胞类型，包含了大约85%活的表皮细胞。角质层是复扁平上皮细胞。角质细胞因含有大量的角蛋白而得名，在表皮基底层,角质细胞分化、增殖，随着角质细胞产生角蛋白并上移至表皮表面后，发生程序性死亡。角蛋白细胞增殖、分化及凋亡是复杂且严格控制的过程。角蛋白细胞可产生很多细胞因子和生长因子，包括IL- 1, IL-3, IL-6, IL-8, 集落刺激因子, TNF-alpha, TGF-alpha and beta, 成纤维细胞生长因子,  双调蛋白和PDGF。除了保护功能之外，角蛋白细胞在组织稳态、伤口恢复、癌症以及皮肤基因治疗上有着重要的作用。人角蛋白细胞能表达粘附分子和细胞因子，这说明了它能参与皮肤免疫和动态平衡。

        <2100>人表皮角质细胞（HEK-n）-新生和<2110>人表皮角质细胞（HEK-a）-成人分别提取于新生儿和成人的表皮组织，于原代冻存。每管含有细胞数>5×105 cells/ml，此细胞通过Cytokeratine-8, -18 and -19免疫荧光染色验证，经测试不含有HIV-1、HBV、HCV、支原体、细菌、酵母和真菌。细胞可以达到15倍增。

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储存：液氮

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用途：科研

The epithelial layer of the skin provides an essential function as a protective barrier against insult from the outside environment. The major cell type in this layer is keratinocytes which consists around 85% of living epidermal cells. Kertinocytes are the cells of stratified squamous epithelia. It is so named because its most abundant protein is keratin. Keratinocyte divide and are thus generated in the basal layer of the epidermis; this division is followed by a programmed death as they produce keratin and move up to the surface of the epidermis. Keratinocyte proliferation, differentiation, and apoptosis are a complex and carefully choreographed process [1]. Keratinocytes have been demonstrated to produce a wide range of cytokines and growth factors, including IL- 1, IL-3, IL-6, IL-8, colony-stimulating factors, TNF-alpha, TGF-alpha and beta, fibroblast growth factor, amphiregulin and PDGF [2, 3]. Besides the protective function, keratinocyte also plays a central role in tissue homeostasis, wound healing, cancers, and skin-based gene-therapy. Human keratinocytes express adhesion molecules and cytokines indicating their participation in skin innate immunity and homeostasis in vivo [4, 5].

HEK-a from ScienCell Research Laboratories are isolated from human adult epidermis. HEK-a are cryopreserved on primary culture and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HEK-a are characterized by immunofluorescent method with antibodies to cytokeratine-8, -18 and -19. HEK-a are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HEK-a are guaranteed to further expand for 15 population doublings in the conditions provided by ScienCell Research Laboratories.

Reference
[1] Eckert, R. L., Efimova, T., Dashti, S. R., Balasubramanian, S., Deucher, A., Crish, J. F., Sturniolo, M. and Bone, F. （2004） Keratinocyte survival, differentiation, and death: many roads lead to mitogen-activated protein kinase. J Investig Dermatol Symp Proc 7（1）:36-40.
[2] Luger, T. A. （1992） Epidermal cytokines and growth factors. Marcel Dekker, Inc., New York , pp. 147-162.
[3] John C. Ansel, Jay P. Tiesman, John E. Olerud, James G. Krueger, Jeffrey F. Krane,t David C. Tara, Gary D. Shipley, Debra Gilbertson, Marcia L. Usui,I and Charles E. Hart （1993） Human Keratinocytes Are a Major Source of Cutaneous Plaet-derived Growth Factor. J. Clin. Invest. 92:671-678.
[4] Song, P. I., Park, Y. M., Abraham, T., Harten, B., Zivony, A., Neparidze, N., Armstrong, C. A. and Ansel, J. C. （2004） Human keratinocytes express functional CD14 and toll-like receptor 4. J Invest Dermatol 119（2）:424-32.
[5] de Panfilis, G., Semenza, D., Lavazza, A., Mulder, A. A., Mommaas, A. M. and Pasolini, G. （2004） Keratinocytes constitutively express the CD95 ligand molecule on the plasma membrane: an in situ immunoelectron microscopy study on ultracryosections of normal human skin. Br J Dermatol. 147（1）:7-12.