Many animal viruses possess the ability to agglutinate erythrocytes. In most but not all cases hemagglutination is due to the virus particle itself, and appears to result from the mechanical bridging of two or more erythrocytes by virus particles which attach to receptor sites on each erythrocyte (1, 2). Thus, attachment of virus particles to erythrocytes is a prerequisite for hemagglutination, and prevention of absorption of virus prevents hemagglutination.
Among the enteroviruses, many ECHO viruses and some strains of Coxsackie B3 virus agglutinate human erythrocytes (3-7), and the evidence indicates that hemagglutination is due to the virus particle itself (3, 5, 6). The precise mechanism of attachment of enteroviruses to cells is unknown. Chymotrypsin treatment of erythrocytes prevents the absorption of some ECHO viruses (8). This suggests that the receptor sites on the erythrocyte may be at least in part protein in nature.
The present communication is concerned with the mechanism of attachment of enteroviruses to cells. It is shown that sulfhydryl reagents block the hemagglutinating activity of enteroviruses. Treated virus fails to absorb to erythrocytes. Thiol compounds restore the hemagglutinating activity of enteroviruses treated with mercaptide-forming sulfhydryl reagents. The effect of sulfhydryl reagents on the infectivity of some enteroviruses is also described.