The Neuraminidase Yield-Reduction Bioassay of Human and Other Interferons 1

Abstract

Summary

The production of neuraminidase by the recombinant influenza virus X7(F₁) in human, monkey, rabbit, hamster, mouse, and chicken cell cultures is inhibited by interferon. Described is a new enzyme assay for neuraminidase that can be applied to the bioassay of interferons. The advantages of this interferon bioassay are its sensitivity, reproducibility, rapidity, and convenience.

We thank Mary Dixon, Joyce F. Otto, and Christine Schoenherr for their excellent technical assistance.

Note added in proof: Experiments subsequent to this manuscript have revealed that the production of neuraminidase in the RK-13 cell line is variable and at times too low for use in an interferon assay.

Note added in proof: Low yields of neuraminidase have recently been obtained in the RK-13 rabbit cell line, an observation which makes this line unsuitable for the neuraminidase bioassay. However, high neuraminidase yields are obtained in another interferon-sensitive line of rabbit skin (RS) cells.