Production of Hemagglutinin by Mumps and Influenza A Viruses in Suspended Cell Tissue Cultures.

Abstract

Suspended cell cultures of various chick embryo tissues were prepared in Erlenmeyer flasks containing 3 cc. of a nutrient medium consisting of 3 parts of balanced salt soln. and 1 part of Simm''s ox-serum ultrafiltrate. In maintaining the cultures, the nutrient fluids were removed at frequent intervals and fresh fluid added. Subcultures were carried out at infrequent intervals by inoculating the pooled supernatant fluids into flasks containing fresh tissue. An egg-adapted strain of mumps virus was propagated readily in such a culture system containing amni-otic membrane fragments and was carried through 2 subcultures during a 32-day period. During this period a calculated increase in mumps virus occurred of the order of 1.3 X 1017, as based on the egg infectivity titer of the tissue culture fluids, and of the order of 3.3 X 1014, based on the hemagglutinin titer. The PR8 strain of influenza A virus was likewise shown to propagate with the production of hemagglutinin in cultures of amniotic membrane, allantoic membrane, or brain. The presence of measurable amts. of hemagglutinin in tissue cultures provides a convenient means of following, within certain limits, the rate and degree of multiplication of mumps and influenza virus in a simple system that is readily subject to exptl. modification.