Virulence of wtLCMV and rLCMVs in CBA/NSlc mice and DBA/1JJmsSlc mice: (a,b) Changes in body weight and survival rate of CBA/NSlc mice. Seven-week-old female CBA/NSlc mice (5 mice per group) were intraperitoneally (i.p.) infected with 1.0 × 102 focus-forming units (FFU) of wtLCMV, rwtLCMV, or various mutated rLCMVs. (c,d) Changes in body weight and survival rate of DBA/1JJmsSlc mice: Eight-week-old female DBA/1JJmsSlc (5 mice per group) were i.p. infected with 1.0 × 102 FFU of wtLCMV or various mutated rLCMVs. Error bars in Figure 4a,c indicate standard errors of the mean. Asterisks indicate that significant differences were observed between the mean body weight of mice infected with medium alone and that of mice infected with LCMVs, displayed in the same colors.