An Immunological Study of Avian, Viral and Bacterial Neuraminidase Based on Specific Inhibition of Enzyme by Antibody

Abstract

SUMMARY: Antisera were prepared to several strains of influenza virus (grown in the chick embryo), to purified Vibrio cholerae neuraminidase and to partially purified neuraminidase from chick chorioallantois. The ability of the antisera to inhibit the action of each enzyme on substrates of different molecular weight was tested. The substrates used and their molecular weights were sialyl lactose (640), fetuin (48,000) and ovine submaxillary gland mucin, OSM (1 x 10⁶). Antiserum to V. cholerae and avian neuraminidase inhibited strongly the action of the homologous enzyme on each substrate. Antiserum to viral neuraminidase inhibited almost completely homologous action on fetuin and OSM but only partially the action on sialyl lactose. LEE influenza virus was grown in embryonated eggs and in cultures of calf kidney cells and from each preparation a soluble neuraminidase was isolated. Antiserum to the egg-grown virus inhibited the enzyme of both viruses not only in the intact virus particle, but also after separation in the form of a soluble, low molecular weight product. There was little or no serological cross-reaction between any enzyme and heterologous antisera, with one exception. Antiserum to avian neuraminidase partially inhibited (fetuin, but not sialyl lactose, as substrate) the soluble enzyme derived from egg-grown LEE virus, but not from virus grown in cultures of calf kidney cells. It was concluded that the soluble enzyme prepared from LEE virus is a virus specific product but also carries some antigenic determinants characteristic of host specificity.