Skin tissue. Fluorescent deconvolution light micrograph of a section through the epidermis (skin), showing human beta-defensin-2 (hBD-2) antimicrobial proteins (blue) in the keratinocyte cells. Keratinocytes are epithelial cells that produce keratin in the skin's outermost layers. As they are used to seed new skin growth, they are often cultured to produce skin grafts or for testing cosmetics and drugs. Magnification: x400, when printed 10 centimetres wide.