Effect of recombinant alpha A-interferon on DNA synthesis and differentiation of human keratinocytes in vitro

Interferons are known to protect cells against virus infection, to inhibit cell growth in a number of cell lines and also to modulate cell differentiation. Their possible clinical application has now entered its final phase. The aim of this investigation was to study the effect of recombinant alpha A-interferon (r IFN-alpha A) on human keratinocyte DNA synthesis and differentiation in vitro. 3H]-TdR incorporation into DNA was used to quantify DNA synthesis in keratinocyte cultures at varying concentrations of rIFN-alpha A. Cell differentiation was determined using polyacrylamide gel electrophoresis of six specific protein fractions extracted from the keratinocytes. Our results indicate that rIFN-alpha A is a potent inhibitor of keratinocyte DNA synthesis in vitro; it also decreases significantly the amount and synthesis of non-covalently bound keratins while increasing the disulphide cross-linked keratins. No qualitative changes in keratinocyte proteins were observed.