Abstract
In one-step growth experiment of measles virus (MV) in Vero cells at 39C, the appearance of MV infectivity was delayed for 24hr and the maximum titer was reduced by approximately 1, 000-fold, when compared with those at 35C. MV infectivity was thermolabile at the high temperature. Penetration was rather enhanced at 39C. By Northern blot hybridization, viral RNAs including 50S genome-sized RNA and mRNAs were first detectable 24hr post-infection (PI) at 35C and 36hr PI at 39C, respectively. Rapid degradation of viral mRNAs was not observed in the infected cells at 39C. The synthesis of N, F, and M proteins was relatively reduced at the high temperature and appearance of the other viral protein was delayed, in agreement with the time course of viral RNA synthesis. All these data suggest that less efficient synthesis of viral RNA, restriction of synthesis of N, F, and M proteins at translational level and thermolability of infectivity are all involved in the suppressed MV production in Vero cells at 39C.
