Figure 4. Detection of VNA titer after oral immunization and survivorship after challenge.

Dogs were orally immunized with 1×10⁸ FFU of LBNSE-dGM-CSF, LBNSE, or DMEM. Peripheral blood was collected at 2, 3, 4 and 5 weeks post immunization for VNA test by RFFIT A. At 5 weeks after immunization, immunized dogs were challenged with 4500 MICLD₅₀ of wild-type RABV SXTYD01 by injecting it at masseter and temporal muscles. Peripheral blood was collected at 7 days post challenge and the serum was for VNA test B. After challenge, dogs were observed twice a day for 3 months and the numbers of survivors were recorded C. Asterisks indicate significant differences analyzed by one-way ANOVA between the different groups. (*, P < 0.05; **, P < 0.01; ***, P < 0.001).