Expression of protein kinase C isozyme in human Langerhans' cells.

Protein kinase C is a key molecule controlling signal transduction into the cell. We recently reported that protein kinase C II isoenzyme, but neither I nor III isozyme, was expressed in epidermal Langerhans' cells of the adult mouse, and that none of these isozymes was detected in keratinocytes. In this study, we examined the expression of protein kinase C isozymes in human Langerhans' cells in vivo to see whether the expression of protein kinase C II isozyme in Langerhans' cells is a mouse-specific trait. Immunohistochemical studies revealed that protein kinase C II isozyme, but neither I nor III isozyme, was expressed in epidermal Langerhans' cells. None of these isozymes was detected in keratinocytes. These results suggest that the expression of protein kinase C II isozyme in epidermal Langerhans' cells in vivo is not a mouse-specific trait and that protein kinase C II isozyme is a novel phenotypic marker for epidermal Langerhans' cells in human as well as mouse skin.