To establish a rabies virus CVS-11 challenge model in BALB/c mice through intramuscular or intracerebral injection.

The CVS-11 strain propagated in BSR cells with a titer of 2.7×10⁷ FFU/ml was serially diluted 10^-1-10^-7 times to infect 4-week-old female mice through intramuscular or intracerebral injection. The morbidity and mortality of mice were observed after virus challenge. Moreover, brain tissues of all challenged mice were subjected to direct immunofluorescence assay (DFA) and reverse transcription polymerase chain reaction (RT-PCR) to analyze the cause of death. The median lethal doses (LD₅₀) in mice under different challenge methods were determined. Mouse challenge models were established to evaluate the immunoprotective effects of four domestically available rabies vaccines on mice after CVS-11 exposure.

BALB/c mice developed typical neurological symptoms and died 6-12 d after intracerebral challenge and the LD₅₀ was 18.3/0.1 ml. The mice intramuscularly challenged with CVS-11 showed clinical symptoms on 8-15 d and the LD₅₀ was 2.7×10⁵/0.1 ml. DFA results showed that specific yellow-green fluorescence appeared in the brain tissue prints of all dead mice. RT-PCR results showed that all amplified products showed bright bands at about 250 bp. These results suggest that rabies virus infection was the cause of death in mice. The protective effect test results of four different rabies vaccines on the market without immunoglobulin application showed that the survival rate of mice after exposure to one of the vaccines was 50%, and the survival rates of mice immunized with the other three vaccines were all 30%. The above results indicated that the four rabies vaccines provided partial protection for mice exposed to CVS-11 without the use of rabies passive immunization preparations.

This study established rabies virus CVS-11 challenge models in BALB/c mice under different challenge methods and provided a technical platform for related research on rabies and rabies vaccines.

Rabies virus; CVS-11; Animal model