The binding of tissue prokallikrein to isolated human neutrophils

We have investigated the binding of human tissue kallikrein and the corresponding proenzyme to isolated human lymphocytes and neutrophils, respectively, by the means of steady-state binding assays. It was demonstrated that only prokallikrein bound to washed neutrophils in a time-dependent, specific and saturable manner, whereas in vitro binding of activated kallikrein to neutrophils or lymphocytes could be excluded. Our data provide strong evidence for the specific interaction of prokallikrein with intact human neutrophils and indicate a neutrophil surface binding site for the tissue kallikrein precursor which could be involved in kallikrein endocytosis and selective prokallikrein-to-kallikrein conversion.