Figure 9.

Transfer of JEV-elicited CD8⁺ T cells modulates anti-JEV Ab-mediated ADE of ZIKV infection. (A and D) 1-d-old C57BL/6 naive mice were s.c. injected with 3 µl of mock-immune or JEV-immune mouse serum. 6 h later, mice were injected s.c. with ZIKV (10² FFU). (B and E) 1-d-old C57BL/6 naive mice were r.o. injected with 2 × 10⁶ CD8⁺ T cells from EV71-VP1–immune or JEV-exposed mice and injected s.c. with ZIKV (10² FFU) 2 h later. (C and F) Mice were treated as described for B and E except that the CD8⁺ T cells were from EV71-VP1–immune or JEV-exposed mice injected s.c. with 3 µl of JEV-immune mouse sera before s.c. injection of ZIKV (10² FFU). ZIKV viral loads in serum and brain were measured using the FFA at 3 or 8 d after infection. Data are presented as the mean ± SEM and are pooled from two experiments, each with three to six mice/group. *, P < 0.05; **, P < 0.01; ***, P < 0.001 by two-tailed Mann–Whitney U test.