Studies on Hemagglutination by Columbia-SK Virus

Abstract

An improved method for studying hemagglutination by Col-SK virus is described. A stoichiometric relationship is shown to exist between the amount of red cells and of hemagglutinin reacting at the endpoint. Human, rat and guinea pig erythrocytes agglutinate specifically with Col-SK virus in K-veronal buffer at 0 C. At 0 C 100% of the initial virus amount is adsorbed, at 20 C 88%, at 35 C 50%—at infinite time. There is no spontaneous elution. However, approximately 17% of the virus adsorbed at 0 C will elute at 35 C in veronal buffer. Hypertonic salt concentrations inhibit hemagglutination. Hemagglutination was inhibited by a comparatively slight increase in the Na concentration whereas a much more drastic increase in the K concentration is needed to produce the same effect. Both CaCl₂ and MgCl₂ inhibit hemagglutination above 0.01 M concentration. Adsorption proceeds at the same rate in CaCl₂ as in NaCl. Evidence of identity of infectious agent and hemagglutinin includes data on: a) the amount of hemagglutinin and the infectivity titer of nervous tissue from different animal species, b) a definite correlation between hemagglutination inhibition and neutralization titer of specific immune sera, c) the similarity of physical and chemical properties of infectious and hemagglutinating principles.