Hardman, C. S. | Search bioRxiv

bioRxiv2018

Role of NS1 antibodies in the pathogenesis of acute dengue infection

The role of NS1-specific antibodies in the pathogenesis of dengue virus infection is of particular interest to the dengue field, yet remains poorly understood. We therefore investigated the immunoglobulin responses of patients with dengue fever (DF) and dengue hemorrhagic fever (DHF) to NS1. Antibody responses to recombinant-NS1 were assessed in serum samples obtained throughout illness of patients with acute secondary DENV1 and DENV2 infection by ELISA. NS1 antibody titres were significantly higher in patients with DHF compared to those with DF for both serotypes, during the critical phase of illness. Antibody responses were further assessed to NS1 peptides and showed that in both acute secondary DENV1 and DENV2 infection, the antibody repertoire of DF and DHF patients is directed towards distinct regions of the NS1 protein. Further experiments in healthy individuals, with either past severe dengue or past asymptomatic dengue infection revealed that individuals with past inapparent disease mounted antibody responses directed to the same NS1 epitope regions as those with mild acute infection (DF). Our results suggest that the specific epitope target of NS1-antibodies generated by patients could predict disease severity and be of potential therapeutic benefit in aiding vaccine and treatment design.

immunology↗

bioRxiv2018

Quantification of dengue virus specific T cell responses and correlation with viral load and clinical disease severity in acute dengue infection

BackgroundIn order to understand the role of dengue virus (DENV) specific T cell responses that associate with protection, we studied their frequency and phenotype in relation to clinical disease severity and resolution of viraemia in a large cohort of patients with varying severity of acute dengue infection.\n\nMethodology/Principal findingsUsing ex vivo IFN{gamma} ELISpot assays we determined the frequency of dengue viral peptide (DENV)-NS3, NS1 and NS5 responsive T cells in 74 adult patients with acute dengue infection and examined the association of responsive T cell frequency with the extent of viraemia and clinical disease severity. We found that total DENV-specific and DENV-NS3-specific T cell responses, were higher in patients with dengue fever (DF), when compared to those with dengue haemorrhagic fever (DHF). In addition, early appearance of DENV-specific T cell responses was significantly associated with milder clinical disease (p=0.02). DENV peptide specific T cell responses inversely correlated with the degree of viraemia, which was most significant for DENV-NS3 specific T cell responses (Spearmans r = -0.47, p=0.0003). The frequency of T cell responses to NS1, NS5 and pooled DENV peptides, correlated with the degree of thrombocytopenia but had no association with levels of liver transaminases. In contrast, DENV-IgG inversely correlated with the degree of thrombocytopenia and levels of liver transaminases.\n\nConclusions/significanceEarly appearance of DENV-specific T cell IFN{gamma} responses appears to associate with milder clinical disease and resolution of viraemia, suggesting a protective role in acute dengue infection.

immunology↗