Physical-Chemical Factors in Agglutination of Sheep Erythrocytes by Influenza Virus. ∗

Summary

The data indicate that agglutination of sheep erythrocytes by influenza virus (WS strain) is influenced by physical-chemical factors within the test systems, and especially by the hydrogen-ion concentration. Over a relatively wide pH range, agglutination of sheea cells is inhibited by substances present in allantoic fluid, normal and infected. The allantoic fluid inhibition is ineffective in the pH range 5.8 to 6.0. When the test systems are adjusted with pH 5.8 buffer, and 1/2% to 1/4% cell suspensions are employed, sheep erythrocytes may be used with essentially the same results as obtained with chicken cells, for the determination of influenza virus content of allantoic fluids, and for the demonstration of antibodies by the agglutination-inhibition test. The data are significant because of the bearing they have upon the mechanism of virus hemagglutination