THE BINDING OF TISSUE PROKALLIKREIN TO ISOLATED HUMAN NEUTROPHILS

We have investigated the binding of human tissue kallikrein and the co rresponding proenzyme to isolated human lymphocytes and neutrophils, r espectively, by the means of steady-state binding assays. It was demon strated that only prokallikrein bound to washed neutrophils in a time- ependent, specific and saturable manner, whereas in vitro binding of a ctivated kallikrein to neutrophils or lymphocytes could be excluded. O ur data provide strong evidence for the specific interaction of prokal likrein with intact human neutrophils and indicate a neutrophil surfac e binding site for the tissue kallikrein precursor which could be invo lved in kallikrein endocytosis and selective prokallikrein-to-kallikre in conversion.