Avidin Attachment to Biotinylated Erythrocytes Induces Homologous Lysis Via the Alternative Pathway

Noncovalent attachment of avidin to the membrane of prebiotinylated red blood cells (RBCs) induces lysis via the alternative pathway of complement (APC). Lysis is not speciesdependent; RBCs from humans, rabbits, rats, and sheep were lysed with both autologous and all heterologous sera. Both biotinylated and native cells were not lysed. Lysis was observed at an avidin surface density of about 10' molecules per cell. Acylation of avidin prevents lysis and decreases the positive charge of the avidin. Lysis depends on the length of the cross-linking agent used for the biotin attachment to the membrane. An increase in the length of the cross-linking agent was accompanied by an enhancement of the lysis and the agglutination titer of biotinylated RBCs in a solution of