Enveloped virus- and lectin-induced structural change in erythrocyte lipid bilayer: Dependence on species of erythrocyte and on the multivalence of the agglutinin

Attachment of influenza virus or concanavalin A (Con A) to avian or amphibian erythrocytes causes the erythrocyte membrane lipid bilayer to become more fluid, as detected by spin-label electron spin resonance. No change in bilayer fluidity occurs upon agglutination of avian erythrocytes pretreated with the microtubule-disrupting drug colchicine or agglutination of mammalian erythrocytes, which lack microtubules. The change in bilayer fluidity upon agglutination of chicken erythrocytes appears to require crosslinking of receptor molecules. The hemagglutinin glycoprotein isolated from influenza virus by treatment with bromelain and the succinylated derivative of Con A bind to receptors, but do not crosslink them and do not cause a change in lipid bilayer fluidity. Multivalent aggregates of influenza virus hemagglutinin, isolated by treatment with Triton X-100 followed by removal of the detergent, are able to induce an increase in erythrocyte lipid bilayer fluidity. Erythrocytes pretreated with succinyl-Con A are agglutinated by antibody to Con A, resulting in an increase in membrane bilayer fluidity. These results support the hypothesis that the fluidity change in the avian erythrocyte membrane induced by virus and lectin attachment involves lateral rearrangement of receptor glycoproteins in the plane of the membrane mediated by microtubule-like systems.