Fig. 2. Complement-mediated virolysis with ZIKV-cross-reactive antibodies is associated with protection from subsequent DHF/DSS and symptomatic DENV infection.

(A-D) Pre-infection plasma samples prior to DF (green; n=31) vs. DHF/DSS (gold; n=33) were incubated with mature DENV2, mature DENV3, ZIKV, and YFV virions. (A,B) Left panel, 1:10 dlution of plasma; right panel, 1:30 dilution of plasma. (E) Pre-inapparent (blue circles; n=30) and pre-symptomatic (orange circles; n=29) secondary DENV3 infection plasma samples were incubated with ZIKV virions. After incubation with plasma samples in the presence of guinea pig complement, mixtures were freeze-thawed once, followed by RNAse A digestion and RNA extraction from intact virions. Virion lysis was quantified by measuring viral RNA via RT-qPCR (to measure the number of genome copies) and calculated as percentage (%) of virion lysis as described in Methods. Shown are median NT₅₀ (middle line), 25^th to 75^th percentile (box), and 5^th to 95^th percentile (whiskers) as well as the raw data (points). Asterisks indicate Benjamini-Hochberg-adjusted p-values for Mann-Whitney U tests (****p < 0.0001, and ns, non-significant).