Protection of Anti-Dengue Virus Nonstructural Protein 1 Antibodies in the Wild Type and Humanized Mouse Models

  • 李 涵

Student thesis: Master's Thesis


Dengue virus (DENV) infection may cause dengue fever or even life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) Currently there are no approved vaccines or antiviral therapies We previously found that the anti-nonstructural protein 1 (NS1) antibodies (Abs) could cross-react with endothelial cells and platelets and cause their dysfunction due to a molecular mimicry with host self-antigens The Abs against C-terminus-deleted NS1 provided protective effects both in cell culture and in mice This NS1 with a deletion at C-terminal amino acids 271-352 was designated ΔC NS1 In addition the Abs against consensus envelope protein domain III (cEDIII) of which the amino acid sequences are consensus among four serotypes and which was developed by our collaborators had neutralizing activity against all the four serotypes of DENV We therefore developed a recombinant NS1 by fusing cEDIII and ΔC NS1 We immunized mice with cEDIII-ΔC NS1 proteins encapsulated in the polymer-based nanocomplex as adjuvant The cEDIII-ΔC NS1 proteins did not cause acute toxicity or prolonged bleeding in mice An ELISA-based assay showed that the immunization provoked a higher Ab response for cEDIII-ΔC NS1 than ΔC NS1 In addition anti-cEDIII-ΔC NS1 Abs could neutralize DENV infection in a plaque reduction test Anti-cEDIII-ΔC NS1 Abs also provided therapeutic effect in DENV-infected wild type (WT) mouse model We further demonstrated that monoclonal antibody (mAb) 2E8 which did not recognize the C-terminal region of DENV NS1 could provide therapeutic effects in DENV-infected WT mice So far there is no ideal animal model for dengue disease studies Because mice are not natural host for dengue the advantages of using humanized mice include higher susceptibility to DENV and enhanced opportunity to investigate human cell responses to DENV infection We have established two models of humanized mice The NOD/SCID IL2Rγnull mice were reconstituted with human hematopoietic stem cells (HSCs) or human peripheral blood mononuclear cells (PBMCs) Passive immunization with anti-ΔC NS1 Abs could reduce DENV-induced mouse-tail prolonged bleeding time in human HSC-engrafted mice In human PBMC-engrafted mice DENV infection induced severe hemorrhage in local skin Importantly passive immunization with mAb 2E8 reduced hemorrhage Taken together the cEDIII-ΔC NS1 protein and mAb 2E8 are potential candidates to provide protection against DENV infection
Date of Award2014 Sep 2
Original languageEnglish
SupervisorChun-Keung Yu (Supervisor)

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