Localization of vitronectin (S-protein of complement) in normal human skin.

Vitronectin, now known to be identical to serum spreading factor and to S-protein of complement, is a multifunctional glycoprotein involved in the adhesion and spreading of cells and in the complement and coagulation pathways. The distribution of vitronectin in normal human skin was investigated with immunofluorescence using polyclonal antibodies, and with an avidin-biotin peroxidase complex technique, using polyclonal as well as monoclonal antibodies. Vitronectin immunreactivity was found to be localized on the elastic fibres in the dermis. Both the thin fibres in the papillary dermis and the thicker elastic fibres in the reticular dermis were stained. No crossreactivity was found between vitronectin and serum amyloid P component, known to bind to elastic fibres. The two proteins were immunohistochemically localized to the same structures in the skin. The distribution of vitronectin in the dermal tissue established in this study provides a basis for further studies of the function and behaviour of vitronectin in health and disease.