Zika convalescent macaques display delayed induction of anamnestic cross-neutralizing antibody responses after dengue infection

Figures & data

Fig. 1 Kinetics of cross-reactive antibody responses.

Relative binding antibody (bAb) levels against whole ZIKV and DENV-2 were examined using ELISA. The kinetics of binding IgM in serum that was collected longitudinally from (a) DENV-2 only (ZIKV naïve) infected animals (n = 4), (b) ZIKV-infected animals prior to DENV-2 infection (n = 5). The kinetics of binding IgG in serum that was collected longitudinally from (c) DENV-2 only (ZIKV naïve) infected animals (n = 4), (d) ZIKV-infected animals prior to DENV-2 infection (n = 5). Statistical significance was determined using multiple unpaired t-tests and corrected for multiple comparisons using the Holm-Sidak method. A p < 0.05 was considered significant and * indicates significant difference between groups

Fig. 2 ZIKV-infected animals display little or no cross-neutralizing antibody responses against DENV-2.

Percentage neutralization of (a) ZIKV and (b) DENV-2 by serum that was collected longitudinally from DENV-2 only (ZIKV naïve) (n = 4) and ZIKV-infected animals prior to DENV-2 infection (n = 5). Line represents PRNT₅₀ titres

Fig. 3 ZIKV immune animals display delayed anamnestic cross-neutralizing antibody responses after DENV-2 infection.

Kinetics of neutralizing antibody responses against DENV-2 using serum that was collected longitudinally from DENV-2 only (ZIKV naïve) and ZIKV-infected animals at (a) day 0, (b) day 1, (c) day 4, (d) day 7, (e) day 14, and (f) day 56 after DENV-2 infection (n = 5). Line represents 50% neutralization

Kinetics of DENV-2 viremia

	Log plasma viral loads ± SD
Days post-infection	DENV-2 only infected animals	ZIKV-infected animals
1	1.7 ± 0.0	1.7 ± 0.0
2	3.1 ± 1.0	1.8 ± 0.2
3	3.1 ± 1.0	4.0 ± 0.7
4	3.5 ± 1.2	5.4 ± 0.4
5	4.7 ± 0.6	6.5 ± 0.6
7	4.4 ± 0.3	3.5 ± 1.3
14	2.3 ± 1.1	1.7 ± 0.0
28	1.7 ± 0.0	1.7 ± 0.0
56	1.7 ± 0.0	1.7 ± 0.0

(SD) Standard deviation

Fig. 4 ZIKV infected animals display delayed binding antibody responses after DENV-2 infection.

Kinetics of binding antibody (bAb) responses against DENV-2 in serum showing relative levels of (a) IgM and (b) IgG against DENV-2 using serum that was collected longitudinally from ZIKV-infected animals 1, 4, and 7 days after DENV-2 infection (n = 5). Percentage OD₄₅₀ values relative to each animals day 56 post-ZIKV infection (day 0 DENV-2) values are shown. Line represents day 0 vales. Statistical significance was determined using multiple unpaired t-tests and corrected for multiple comparisons using the Holm-Sidak method. A p < 0.05 was considered significant and * indicates significant difference between groups

Fig. 5 IgG1 is the primary subclass of IgG in serum from ZIKV naïve and infected animals prior to and after infection with DENV-2.

Relative levels of (a) DENV-2 and (b) ZIKV binding IgG1, IgG2, and IgG3 in serum that was collected at day 14 and day 56 post-infection from DENV-2 only (n = 4) infected animals. Relative levels of (c) DENV-2 and (d) ZIKV binding IgG1, IgG2, and IgG3 in serum that was collected at day 14 and day 56 post-infection from ZIKV-infected animals prior to DENV-2 infection (n = 5). Relative levels of (e) DENV-2 and (f) ZIKV binding IgG1, IgG2, and IgG3 in serum that was collected at day 1, 4, 7, and 56 post-infection from ZIKV-infected animals after DENV-2 infection (n = 5). Statistical significance was determined using one-way ANOVA and differences between time-points were determined by post-hoc analysis using Tukey’s multiple comparisons test. A p < 0.05 was considered significant. Error bars represent standard error

Fig. 6 Serum from ZIKV infected animals collected after infection with DENV-2 demonstrate antibody dependent enhancement at a dilution of 1:100.

Fold enhancement of DENV-2 infection in K562 cells using serum that was collected (a) from ZIKV-infected animals (n = 5) prior to DENV-2 infection and (b) at day 56 after DENV-2 infection. Statistical significance was determined using One-way ANOVA and differences between time-points were determined by post-hoc analysis using Tukey’s multiple comparisons test. A p < 0.05 was considered significant. (c) Percentage neutralization of DENV-2 using serum that was collected at day 56 post-infection from animals that was simultaneously infected with ZIKV and DENV-2 (n = 5). (d) Fold enhancement of DENV-2 infection in K562 cells using serum that was collected at 56 days from rhesus macaques that were simultaneously infected with ZIKV and DENV-2 (n = 5). Statistical significance was determined using One-way ANOVA and differences between time-points were determined by post-hoc analysis using Tukey's multiple comparisons test. A p < 0.05 was considered significant. Error bars represent standard error