BINDING OF BIOTINYLATED ERYTHROCYTES TO A VIDIN-COATED SURFACE INDUCES THEIR LYSIS BY HOMOLOGOUS COMPLEMENT - A NEW APPROACH TO DEVELOPMENTOF TARGET-SENSITIVE CARRIERS FOR DRUG TARGETING

Red blood cells biotinylated with short (B1) and long (B2) biotin este rs (B1- and B2-RBC) specifically bind to avidin-coated surface, while at a low surface density of avidin BZ-RBC binds better than B1-RBC. B- RBC bound with avidin-coated surface, but not free B2-RBC, were lysed by a homologous complement, with B2-RBC lysed better than B1-RBC. Bind ing of B-RBC to avidin-coated surface needs lesser surface density of avidin than lysis of B-RBC bound to immobilized avidin. B-RBC bound to combined avidin-fibrinogencoated surface masks fibrinogen from the an ti-fibrinogen antibody added to the solution, indicating that the part icular site of the contact between B-RBC and immobilized avidin is una ccessible for the complement-size molecules the solution. These data a llows the suggestion that the contact with immobilized avidin might in duce considerable reorganization of the biotinylated components of RBC 's membrane, its destabilization and lysis by the complement, while th e contact between biotinylated membrane and immobilised avidin is unac cesible for the complement. In terms of the targeting of drugs these r esults suggest a new approach to development of target-sensitive immun oerythrocytes.