[Contribution to the antigenic study of influenza viruses in animals. I.–Neuraminidase of the equine influenza viruses (author’s transl)].

The research article focuses on the study of neuraminidase antigenic properties in equine and fowl influenza viruses and shows a close connection between these viruses regardless of their animal origin.

Research Details

• The researchers adopted the revised classification system of the World Health Organisation (WHO) to study the influenza viruses in animals.
• The neuraminidase (Neq2) of the fowl influenza virus A/Duck/Ukraine/63 (Hav7 Neq2) was noted to be the same as that of the equine virus A/equi 2/Miami/63 (Heq2 Neq2).
• Similarly, the neuraminidase of the A/Chicken Germany “N”/49 virus was revealed to be the same as the equine virus A/equi 1/Prague/56.
• The study confirmed the close relationship between the Neq2 neuraminidases despite their various animal origins.

Antibody Titration Strategy

• The fowl strain Hav7 Neq2 was enlisted as a useful means for the titration of anti-Neq2 antibodies in the serum of animals injected with the equine virus Heq2 Neq2.
• While anti-Neq1 antibodies of animals immunized with the Heq1 Neq1 virus showed a little inhibition of the neuraminidase in the Hav2 Neq1 fowl strain, the recommendation was to use the H72 Neq1 recombinant for measuring anti-Neq1 antibodies of equine origin.

Antigenic Characterization

• Further to this, the antigenic characterization of various equine influenza strains, isolated post 1967, was also accomplished through a study of their respective neuraminidases.
• Similar to neuraminidases, hemagglutinins from strains that belong to the sub-type A equi2 showed a strong connection.
• However, a minor antigenic variation involving both surface antigens was observed between the strain A equi 1/Prague/56 and a strain of the same sub-type isolated in 1973.