Effect of Cold Passage on Reproductive Capacity at Various Temperatures of Several Type 3 Poliovirus Strains. ∗

Abstract

Summary

The reproductive capacity of several type 3 poliovirus strains was studied at 23°C, 37°C, and 40°C. There was marked variation in the capacity of the strains to replicate at different temperatures. Two wild strains, L-97 and L-38, were serially passed at 23°C. After 14–16 passages at 23°C, each strain lost its growth potential at 40°C while its growth potential at 23°C increased. A plaque pool obtained from the L-97 strain had the interesting ability to replicate well at all 3 temperatures. This plaque pool did not entirely lose its growth potential at 40°C even after 16 passages at 23°C. A plaque obtained from L-38 was passed at 23°C. There was a marked alteration in reproductive capacity at various temperatures of this particular plaque pool during a single passage, the third, at 23°C.