Figure 3
The immunological efficacy of different viral passages during adaptation to CECs. Adult mice were injected i.p. with vaccine candidates or PBS as a negative control. At 14 days after the first immunization, the adult mice were challenged by injecting i.c. with serial ten-fold dilutions of standardized viruses of the CVS strain. The numbers of mice dying of rabies between 4 and 14 days post-challenge were recorded, and the protection index was determined as the LD50 ratio of the experimental group to the LD50 of the control group.