Characterization of DENV-specific antibodies from soropositive adult volunteers vaccinated with tetravalent vaccine TV003

• Grant number: 15/03933-3
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2015
• End date: August 31, 2018
• Field of knowledge: Biological Sciences - Immunology - Cellular Immunology
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Esper Georges Kallás
• Grantee: Cássia Gisele Terrassani Silveira
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The humoral immune response and the antibody (Ab) neutralizing potential are important features for controlling dengue virus (DENV) infection and acquiring protective immunity against this pathogen. In this context, the plaque reduction neutralization test (PRNT) is currently the accepted approach to measuring DENV-neutralizing and protective profile of antibodies, and to assessing the immunogenicity of dengue vaccine. However, evidence suggests that the correlation between the PRNT-based data and the effective protection from DENV infection is not absolute. The aim of this proposal is to characterize the expansion kinetic of antibody-secreting plasmablasts and the plasmablasts-derived Ab repertoire circulating in the peripheral blood from healthy and previously-DENV infected adults inoculated with the tetravalent vaccine TetraVax-DV TV003. In this study, plasmablast cells will be identified by flow cytometry before and after vaccination. Single CD27high CD38high B cells derived from peripheral blood of the volunteers with plasmablasts expansion will be individually isolated in 96-wells plates and the respective variable Ig heavy (VH) and light (VL) chain sequences will be amplified and sequenced. The VH and VL Ig sequences will be cloned in expression vectors and the resultant Ab will be investigated regarding its specificity and affinity (by ELISA), and its neutralizing capacity and ability to promote Ab-dependent enhancement (by in vitro assays). This study may provide consistent data regarding the capability of TV003 vaccine on promoting a protective response against DENV infection in humans. (AU)