STUDIES ON THE HEMAGGLUTINATION INHIBITOR AGAINST ASIAN INFLUENZA VIRUS
1959 Volume 9 Issue 2 Pages 138-147
Details
1959 Volume 9 Issue 2 Pages 138-147
Difficulties were often encountered in carrying out hemagglutination inhibition test with Asian influenza virus, for there were non-specific inhibitors against Asian influenza virus in sera of many animals. In addition, the properties of the inhibitor appeared somewhat different from those of inhibitors so far described.
Following experiments were made in order to elucidate the nature of the inhibitor and to estimate its content in sera from various animals.
1) Hemagglutination inhibition titers of egg white and normal sera from nine species of animals against various strains of influenza virus were determined. Changes in their inhibition titers, after various treatments were also examined. A/Adachi/2/57, now used as a standard strain of Asian influenza virus in Japan, was readily inhibited by many of normal animal sera, especially in high titer by horse, swine and guinea pig sera.
2) The inhibitory activity was heat stable, destroyed neither by RDE (crude filtrate of the culture of V. cholerae) treatment nor by trypsin treatment, but was readily destroyed by KIO4 treatment. Marked difference in its inhibition titer against live virus and indicator virus of A/Adachi/2/57 was not observed. A/Adachi/2/57 was neutralized by normal horse serum in embryonated eggs. The neutralizing activity was also inactivated by KIO4 treatment. Based upon these results, the inhibitor against A/Adachi/2/57 is considered to be distinct from α and β inhibitors, and the term γ inhibitor was proposed. Comparison of properties of α, β and γ inhibitors and their contents in sera of various animals were diagramatically shown.
3) A correlation was found between hemagglutination inhibition by human antisera and that by inhibitor, at least with six strains of Asian influenza virus so far examined. A/Kumamoto/Y5/57, which was not inhibited by γ inhibitor in hemagglutination, was not also neutralized by γ inhibitor in embryonated eggs.
4) Addition of two volumes of M/100 KIO4 to one volume of sample was recommended as a useful procedure in practice in order to remove γ inhibitor in hemagglutination inhibition test. This treatment did not seriously affect specific antibody titer.
