Predesquamin extends maturation of cultured keratinocytes

Predesquamin is a glycoprotein that we have isolated from human epidermis. Its monospecific polyclonal antibody immunolocalizes to the lower stratum corneum. We have previously found that it is not expressed ordinarily in primary keratinocyte cultures, but that it is expressed in a serum-containing medium that is supplemented with interferon-gamma. Under these conditions, we observed larger outer squames and a more mature pattern of desquamation. We now demonstrate, by adding predesquamin directly to the culture medium without the cytokine, that the morphological changes are caused by predesquamin (and the role of IFN-gamma in the previous experiment was to stimulate the expression of predesquamin).