Ultrastructural effects of recombinant gamma-interferon on cultured human keratinocytes

To extend our initial observations that recombinant gamma-interferon (r gamma IFN) influences the growth and differentiation of normal cultured human keratinocytes, we studied the electron microscopic changes induced by r gamma IFN. Treatment of cultured human keratinocytes with 10(3) units/ml (7.1 nM) of r gamma IFN produced a shift toward an increasing percentage of attached cells that had a mature-type, differentiated appearance rather than a basal type of proliferating cell, as observed in control, untreated cultures. This report extends the number of cell types that can be influenced by r gamma IFN at the ultrastructural level and supports the notion that r gamma IFN can influence both growth and maturation of normal cultured human keratinocytes.