Abstract
I. Properties of the hemagglutinin:
Experiments on the hemagglutination reaction by Japanese B encephalitis virus, described by A. B. Sabin et al, in 1950, were performed.
The results are summarized as follows.
1) All of six strains of newly isolated virus agglutinated erythrocytes of chicks from 24 hours to 3-4 weeks after hatching.
2) Optimal conditions for the reaction as to the method of extraction, the nature of the diluent, pH, temperature, the nature and age of erythrocytes, etc. were determined.
3) The relationship between infecting virus particles and hemagglutinating agent was studied by means of absorption, filtration through Seitz discs, high-speed centrifugation, chemicals, methanal precipitation, etc. There seemed to be no constant relation between hemagglutinating agent and LD50 of the infecting agent. It was assumed that the hemagglutionating agent was not the virus particle itself.
II. The hemagglutination inhibition tests with human sera and immune guinea pig sera.
1) One hundred and seven human sera of suspected encephalitis cases and 153 samples of immune guinea-pig sera were tested by means of hemagglutination inhibition test and complement-fixation reaction. The correlation index of these two reactions was 0.60 and 0.80, respectively.
2) Hemagglutination inhibition was hardly to be recognized during the first week after the onset of disease; the correlation with complement fixation became higher after the second week. H. I. test may be utilized as supplemental method for the diagnosis of was Japanese B encephalitis.
3) Removal of normal inhibitor by treatment of sera with chloroform as reported by earlier worker was not confirmed.
4) Small scale experiments with immune guinea-pig sera did not show close parallelism between H. I. test and virus neutralization reaction.
