FIG 6.

Ex vivo T cell reactivity to ZIKV or DENV LFn fusion proteins in ZIKV or DENV convalescence. PBMC samples from ZIKV IgM-positive subjects collected during the convalescent phase of infection were subjected to homologous LFn NS3 protease and helicase protein stimulation in IFN-γ (A) and TNF-α (B) LFn ELISPOT ex vivo experiments. LFn-ZIKV-NS3-P IFN-γ, red-shaded circle; LFn-ZIKV-NS3-H IFN-γ, red-outlined circle; LFn-ZIKV-NS3-P TNF-α, red-shaded diamond; LFn-ZIKV-NS3-H TNF-α, red-outlined diamond. PBMC samples from DENV IgM-positive subjects collected during the convalescent phase of infection were subjected to homologous LFn NS3 protease and helicase protein stimulation in IFN-γ (C) and TNF-α (D) LFn ELISPOT ex vivo experiments. LFn-DENV-NS3-P IFN-γ, blue-shaded circle; LFn-DENV-NS3-H IFN-γ, blue-outlined circle; LFn-DENV-NS3-P TNF-α, blue-shaded diamond; LFn-DENV-NS3-H TNF-α, blue-outlined diamond. Responses are expressed as the number of secreting cells per 10⁶ PBMCs and are considered positive if the net numbers of spot-forming cells (SFC) per 10⁶ are ≥55, are greater than four times the mean background, and are three standard deviations above the background. Comparison of IFN-γ⁺ ZIKV/DENV NS3 protease (black-shaded bars) and helicase (black-outlined bars) and TNF-α⁺ ZIKV/DENV NS3 protease (gray-shaded bars) and helicase (gray-outlined bars) T cell responses in ZIKV and DENV subjects (E) and between recent and convalescent (Conv) phases of ZIKV (F) or DENV (G) infection. The magnitudes of responses are expressed as geometric positive means ± standard deviations, and statistical analyses were performed with Mann-Whitney U test. *, P < 0.05.