Studies on Hemagglutination by Columbia-SK Virus

Summary

1. 1. An improved method for studying hemagglutination by Col-SK virus is described.

2. 2. A stoichiometric relationship is shown to exist between the amount of red cells and of hemagglutinin reacting at the endpoint.

3. 3. Human, rat and guinea pig erythrocytes agglutinate specifically with Col-SK virus in K-veronal buffer at 0 C.

4. 4. 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.

5. 5. 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.

6. 6. 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.