Figure 3.

Histopathology during D83-144 infection. (a–i) Representative slides from D83-144-infected mice at 2 and 3 days post-infection (p.i.) are shown at 10× and 40× magnification. Controls for comparison are from liver sections from 2 day p.i. mock-infected mice, shown as control (a,b). At 2 and 3 days p.i. (d,e,g and h, respectively) D83-144 infection leads to activation of hepatocytes shown as binucleation or nuclear pleomorphism. To detect active replication in the liver, sections were immunostained with rabbit-anti-DENV-NS3, as described in Methods. Positive (red) signal was observed for DENV NS3 in the D83-144 2 (f) and 3 (i) days p.i. slides, but not in the control antibody-stained slide (c); DAPI was used to stain nuclei (blue). Further, control (j) or 2 day p.i, (k) spleen samples were stained for NS3 (positive red stain on day 2). Splenomegaly in D83-144 was calculated as a function of spleen mass to total body mass (g) and compared with ANOVA and Dunnett’s post-test: day 1 p = 0.0029, day 2–4 p < 0.0001. Results are from two independent experiments; day 0 and 1, n = 4; day 2 and 3 n = 7; day 4 n = 2.