Studies on the antibody repertoire in a Dengue virus immune subject and isolation of neutralizing antibodies by phage display technology

Abstract

Dengue Virus (DENV) is known as the causative agent of Dengue Fever and Dengue Hemorrhagic Fever / Dengue Shock Syndrome (DHF/ DSS). Infection with one of the serotypes elicits long-term, homotypic protection but does not protect from the risk of development of DHF/DSS upon subsequent infection with other serotype(s) via a mechanism known as Antibody-Dependent Enhancement (ADE) by cross-reactive, non-neutralizing antibodies. Previous studies using mouse mAbs demonstrated that the Ectodomain III (EDIII) in the E protein of DENV is the primary target of the most potent neutralizing antibodies against DENV. Interestingly, the EDIII specific antibodies are much less abundant than the EDI/II-specific antibodies, although they may contribute more significantly to viral neutralization and protection. This study aims to characterize the binding specificity of human convalescent serum from a DENV-2-immune subject, and the potential change in its neutralizing capacity after antibody depletion, to elucidate the role of EDIII in DENV neutralization. In addition, Phage Display Technology was utilized to generate a DENV-immune Fab phage library for investigation of antibody repertoire upon infection, and for identification of EDIII-specific Fabs that are highly neutralizing.