Fig. 3.

Virus detection by qRT-PCR in tissues after secondary homotypic and heterotypic DENV infection. C57BL/6 mice were infected i.p. with (a, b, c) DENV-1 or (d, e, f) DENV-2 and 60 days later, challeged i.p. with DENV-2. At different times post secondary infection (0, 6, 24, 48, 96, and 168 h), mice were euthanized and (b, e) draining lymph nodes (LN) (mesenteric, periportal and celiac) and (c, f) organs (spleen, liver and kidney) were collected. Total RNA was extracted from tissues and DENV-2 RNA was detected by qRT-PCR. Arrows indicate transient viral replication. LN: lymph node. Values represent means ± SEM (n = 6–8/group). Two independent experiments were performed that showed similar results. *p < 0.05, **p < 0.01, ***p < 0.001 determined by one-way ANOVA (dashed line) and Bonferroni's multiple comparison post-test (solid line). The statistical significance of post-test comparisons is only depicted for the DENV RNA peaks that suggest transient replication. Dotted lines show limits of detection.