An investigation of the replication of coronaviruses in suspension cultures of L132 cells

A system is described for the study of the multiplication of two coronaviruses, both of human origin. Low efficiences of adsorption and infectious centre formation were observed. The viruses were found to have a 4–6 hour eclipse phase in L 132 cells at 33° C. Both viruses were completely inhibited by raising the incubation temperature to 39° C, and there was also a depression in the yield of virus at 30° C compared with control cultures maintained at 33° C. “Shift” experiments have indicated that the high temperature-sensitive event occurred fairly late on in the replicative cycle, but the time could not be accurately determined.