Figure 7. Cross-protection of hSCARB2-Tg mice against the 5746 challenge by pre-immunization with live E59.
(A) Surviving 1-d-old hSCARB2-Tg mice were primed with 1×107 pfu of live E59 s.c. (○) or medium (mock) (•) and then challenged with 3×104 pfu of 5746 s.c. after 7 d. Twelve mice in the live E59 pre-immunized group and 10 mice in the mock-treated group were examined. Logrank test was used for statistical analysis. (B) Group of transgenic animals received immunization and/or challenge of EV71 was illustrated. One-day-old hSCARB2-Tg mice were immunized with 107 pfu of live E59 or mock and then challenged on Day 21 of birth with 3×104 pfu 5746 or mock. In another group, 7-d-old hSCARB2-Tg mice immunized with E59 and challenged on Day 21 of birth with 5746 was included. (C) We harvested 5×105 splenocytes from individual mice on Day 28 of birth and subjected them to the IFN-γ and IL-4 ELISPOT assays that were described in the Materials and Methods. Data are representative of the results derived from 2 independent experiments, each with 4 mice per group. (D) Serum samples were also collected from individual mice while sacrificed as following the schedules described in (B) and were assayed for the titer of anti-E59 and anti-5746 neutralizing antibodies described in the Materials and Methods section. The results were expressed as titers for each test sample. Bars correspond to the mean titers for each experimental group. Unpaired student t test with Welch’s correction was used for statistical analysis of (C) and (D).