Respecrins--a new type of compound with targeted action

A new technique for the creation of compounds with targeted action is described. In such compounds, termed respecrins (receptor-specific, screened toxin), a physiologically active component carries an epitope-containing fragment of the target antigen and is screened or masked by antibody specific to this antigen. Interaction of the respecrin with the target cell results in dissociation of this immunocomplex, and thereby activation of the physiologically active component. The kinetics of dissociation of a respecrin during interaction with a cell were investigated by flow cytometry. Possible applications of the principle are illustrated by investigation on the antigen-dependent activation of the mitogenic activity of staphylococcal enterotoxin A.