Figure 6. VNA production and protection by rRABVs after oral immunization.

Groups of 10 ICR mice were orally immunized with 1×10⁷ FFU of LBNSE, LBNSE-GMCSF, LBNSE-Flagellin or DMEM. At 21 days post primary immunization, blood was collected from mice and serum was separated for VNA test by RFFIT (A). After blood collection, booster oral immunization was carried out with the same dose of rRABVs or DMEM. At day 7 post booster immunization, blood was collected for VNA test (B). Then mice were challenged with 50 MICLD₅₀ of CVS-24 and observed daily for 2 weeks, and the numbers of survivors were recorded and compared(C). Asterisks indicate significant differences between the experimental groups as analyzed by one-way ANOVA or Fisher’s exact test (χ²). (*,P<0.05;**,P<0.01;***,P<0.001).