Avidin attachment to biotinylated amino groups of the erythrocyte membrane eliminates homologous restriction of both classical and alternative pathways of the complement.
Lysis of avidin-coated biotinylated sheep red blood cells (RBC) via the classical pathway of homologous (sheep) and heterologous (guinea pig) complement has been studied. The minimal surface density of avidin inducing antibody-dependent lysis via the classical pathway is smaller than that inducing antibody-independent lysis via the alternative pathway. Heterologous lysis via the classical pathway does not depend on the mode of avidin attachment: both biotinylation of membrane amino groups and insertion of biotinyl-lipid into the membrane provide the same lysis of avidin-coated RBCs by guinea pig serum in the presence of anti-avidin antibody. Avidin-free sheep RBC sensitized with hemolytic anti-RBC antibody were lysed by guinea pig, but not by sheep serum, confirming high efficiency of homologous restriction of the complement. However, avidin-coated RBCs were lysed by homologous serum in the presence of anti-avidin antibody at low surface density of avidin attached. The elimination of the homologous restriction depends on the mode of avidin attachment: biotinylation of membrane amino groups provides antibody-mediated lysis via the classical pathway of homologous complement, while insertion of biotinyl-lipid does not provide lysis.
Muzykantov
V R
VR
Institute of Experimental Cardiology, Cardiology Research Center, Moscow, Russia.
Smirnov
M D
MD
Klibanov
A L
AL
D000588:Amines / Q000737:chemistry; D000818:Animals; D000937:Antigen-Antibody Reactions; D001360:Avidin / Q000378:metabolism; D001710:Biotin / Q000737:chemistry / Q000378:metabolism; D003170:Complement Pathway, Alternative; D003171:Complement Pathway, Classical; D004910:Erythrocyte Membrane / Q000737:chemistry / Q000276:immunology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D012756:Sheep
D000588:Amines; D001360:Avidin; D001710:Biotin