| The keratinocyte (KC) is a source of many cytokines that function in the cutaneous immune response and in normal homeostasis. The cytokine investigated in this study, leukemia inhibitory factor (LIF), is a pleiotropic cytokine that influences the growth and function of many diverse cell types. It was found that, in vitro, normal human KC express mRNA for LIF and its receptor, suggesting a potential autocrine or paracrine role for this factor in KC growth. However, LIF on its own does not appear to be a growth regulator for KC since LIF had no effect on KC growth, in vitro. LIF protein was found in the suprabasal layers of normal human skin, as visualized by immunostaining, and detected constitutively at 1-2 pg/mL in KC conditioned media (CM), where it was increased 155-fold after 72 h in high calcium media which induces terminal differentiation. It was also elevated 3-5-fold after a 24 h incubation with interleukin (IL-) 1... |
