Effect of gamma-interferon on lectin-binding glycoproteins in cultured human keratinocytes

We report the effect of exposure of human keratinocyte cultures to human recombinant gamma-interferon (g-IFN) on the expression of glycoproteins. Concanavalia ensiformis agglutinin (Con-A), and Arachis hypogaea agglutinin (PNA) were used to investigate expression of glycoproteins. NP-40 extracts from cultures grown with or without 100 U/ml g-IFN were analyzed by incubation of SDS-polyacrylamide gels with 125I-labeled lectins. Comparison of Con-A binding glycoprotein profiles showed both qualitative and quantitative changes related to the effect of g-IFN. Differences were also apparent after labeling of the gels with PNA. A limited number of components were labeled, with most of the reactivity falling within a couple of diffuse bands with high molecular weight (300 to 360 kDa). These components were strongly labeled in extracts from cells grown in the presence of g-IFN, but weakly reactive in control cultures. Neuraminidase treatment unmasked a 205 kDa PNA binding molecule only when cells were cultured in the absence of g-IFN. These changes are interpreted in terms of increased keratinocyte differentiation induced by g-IFN and demonstrate that glycoproteins bearing carbohydrate residues available to lectins Con-A and PNA have to be taken into account to better understand the complex action of this lymphokine. In inflammatory lesions, such changes in the glycoproteins of keratinocytes expressing HLA-DR antigens remain to be explored.