Abstract
The hypertonic maintenance medium (MM) was examined for influence on virus reproduction and cytopathic effects of Coxsackie B and Echo viruses in experiments with HeLa cells serially cultivated in the hypertonic growth medium (HeLa-O200 cells). The susceptibility of these cells to the viruses was also studied.
1) In the tube titration all the types of Coxsackie B and Echo viruses revealed lower CP titers in the hypertonic MM than in the isotonic MM.
2) In the isotonic maintenance medium the CP titers of the viruses determined on HeLa-O200 cells were lower than those on HeLa cells. The difference, however, was not so apparent as that observed in comparative titration between the hypertonic and isotonic MM.
3) The greatest influence of the hypertonic MM on CP titer was observed with Coxsackie B-2 and Echo-7 viruses. The CP titers of these viruses were 5-6 log lower in the hypertonic MM than in the isotonic MM.
4) These viruses grew equally well in both maintenance media. The influence of the hypertonic MM on cytopathic effect did not appear to result from the inhibition of virus reproduction.
5) When the hypertonic MM was prepared with sucrose for the tube titration of Coxsackie B-2 virus, it was proved to have a mild inhibitory action over the cytopathic effect. The fact denotes that the inhibition of cytopathic effect was not brought about merely by the physical hypertonic condition, but required an increased in electrolyte (Na+).
6) Addition of cystine and glutamine to the hypertonic MM had no influence on the CP titers of the viruses.
