The host cell population and the size of the virus inoculum were selected as variables in the propagation of viruses in mammalian cells in vitro , to learn the effect of each upon virus yield. As a model cultural system, strain HeLa cells and poliomyelitis viruses were employed since cells and virus can be readily and accurately quantitated. The yield of poliomyelitis virus, Type 1, 2 or 3 at the time of destruction of from 90 to 100 per cent of strain HeLa cells was determined by the population of host cells, and not by the size of the virus inoculum. The time required for total destruction of cells to occur was indirectly related to the quantity of virus in the inoculum; it was prolonged from 1.4 to 1.9 times by a reduction in the temperature of incubation from 36°C to 30°C even though equal quantities of virus were produced at each temperature. The yield of poliomyelitis virus, Type 1, 2 or 3, per strain HeLa cell was found upon calculation to range in these experiments from 1.7 to 3.4 log TCID50 (geometric mean, 2.5 log TCID50).
展开▼
