Effect of neuraminidase on potency of inactivated influenza virus vaccines in mice.

The protective effect of neuraminidase was studied in a mouse protection test using isolated neuraminidase of A2/Aichi/68(H3N2) virus and the complete recombinant virus A/eq(Heq-1)-HK(N2) as antigens. Immunized mice were protected against A2/Aichi(H3N2) challenge virus; however, the protection rate was low in comparison to animals immunized with comparable amounts of the complete A2/68(H3N2) virus9 Furthermore there was no cross-protection against A2/Asia/57(H2N2) challenge virus. The protective effect of neuraminidase was not impaired by Tween-ether treatment of the A/eq(Heq-1)-HK(N2) recombinant virus.