Studies on ABO blood substances of influenza A2 virus with special reference to the preventive mechanism due to blood group agglutinins

Abstract

There was a relatively high incidence of group O persons among those affected by influenza A2 infection as previously reported by McDonald and Zuckermann. However, experimental proof of their statistical survey has not been obtained. The object of this study was to show the participation of ABO blood group substance and its antibody in influenza A2 infection.(1) Blood group substances of egg grown influenza viruses were studied by means of the agglutinin-inhibition test and the elution test. Concentrated, washed and methanol treated suspension of influenza viruses did not inhibit the activities of anti-A, anti-B and anti-H agglutinins. The elution test was then carried out by means of using the virus particles adhered on paper strips. The strips were sensitized with sufficient amounts of anti-A (human), anti-B (human) or anti-H (Ulex europaeus) at a low temperature, and washed with chilled normal saline. Excessively bound agglutinins were then liberated from the strips by heating up to 50°C for 20min. The presence of only anti-H agglutinin was proved in thus obtained eluates. This result indicates the content of blood group H substance in influenza A2 virus. The H substance in influenza B virus was also certified by this test method, but its quantity was assumed to be less than that of A2. For the purpose of assuring the H substance, chickens were immunized with concentrated influenza A2 (Hongkong) virus with incomplete Freund's adjuvant. In the sera of 3 out of 5 chickens, a relatively weak complete anti-H and Eisler's agglutinin were determined to have been produced.(2) After the cessation of influenza A2 (Hongkong) epidemic in 1969, 455 individuals' adult human blood samples were collected to determine blood groups, the presence or absence of complete anti-H agglutinin and the titer of hemagglutination inhibition (HI) titer for A2 (Hongkong) virus.Results obtained were:1) No correlation was found between the range of HI titer and the classification of blood groups, ABO, MN, P, Rh and Lewis.2) Incidence of complete anti-H agglutinin in influenza vaccine recipients' and non-recipients' sera were very similar.3) Incidence of complete anti-H agglutinin and HI titer in the sera of influenza A2 (Hongkong) vaccine non-recipients was compared. Frequency of the sera showing HI titer of 1:4 or higher were less in the group of anti-H positive group relative to the anti-H negative group. X2 test of the result, however, showed no significant difference. (Probability≈0.1)(3) Based on the results of the present study, it was assumed that the anti-H agglutinin in nasal or tracheal secretions of group A, B and AB persons could adhere to H substance of influenza A2 virus to inhibit its growth.