The Effect of Environment on the Replication of Poliovirus in Monkey Kidney Cells

SUMMARY: Poliovirus can complete its maturation in monkey kidney cells suspended in semi-solid agar. Infectious particles and the progeny from each infected cell diffuse through the semi-solid agar to form a single plaque in an underlying monkey kidney cell monolayer. Using this technique, the effect of environment on the multiplication of poliovirus in singly infected monkey kidney cells was studied. Under optimal conditions of pH and temperature (pH 7·0–7·4, 37°) one-step growth curves indicated that over 95% of the adsorbed virus particles went into eclipse; that the eclipse phase lasted 3–4 hr.; that the increase in infective virus was exponential and that a yield of 700–1400 infectious particles/infected cell was obtained in 12–14 hr. After about 10 % of the total progeny had formed, the cells began to release virus. Under suboptimal conditions of pH or temperature, the eclipse stage was prolonged. At pH 6·0–6·5 it lasted for 6 hr. and at pH 5·0–5·5 for more than 9 hr. At 25° virus particles were adsorbed and went into eclipse, with the exception of some particles which remained infectious and could be neutralized by antiserum. Thereafter the eclipse stage was strikingly prolonged, and replication proceeded on raising the temperature to 37°.