Immunogenicity of NS4b Dengue 3 Virus Mimotope Presented to the Immune System as Multiple Antigen Peptide System

The availability of random peptide libraries displayed on bacteriophage (RPL) has provided a powerful tool for selecting sequences that mimic binding properties of natural antigen epitopes (mimotopes). These mimotopes can be used for vaccine design, drug development, and diagnostic assays. Several mimotopes have been shown to induce production of antibodies against the natural antigen. We have previously identified four dengue virus mimotopes from a phage-displayed peptide library using antidengue 3 human sera. Three of them showed similarity in their amino acid sequences with the NS4b proteins of dengue. Few studies have examined the role of NS4b proteins in the antibody response to dengue virus infection. A multiple antigen peptide (MAP) system was chemically synthesized containing this mimotope (NS4b MAP), and BALB/c mice were immunized to evaluate its immunogenicity. Antipeptide responses were induced and recognised DENV-3 infected cells as determined by immunofluorescence. The high levels of the IgG2a subtype against NS4bMAP suggest the induction of a Th1-like response. Our findings suggest that the NS4b mimotope might be a useful tool for the development of multiepitope diagnostic assays, dengue virus vaccine design, and pathogenesis studies. 1. Introduction Dengue is currently one of the most important mosquito-borne viral diseases of humans worldwide. Four viruses (dengue virus 1–4) belonging to the family Flaviviridae, genus Flavivirus, are responsible for this disease. Classically, two main syndromes are recognized: dengue fever and dengue hemorrhagic fever/dengue shock syndrome (DHF)/(DSS). The WHO classification of DHF/DSS was reviewed recently, and a new classification (dengue and severe dengue) has been proposed [1]. The dengue virus genome is composed of a linear, single stranded, and positive sense RNA molecule which is translated into a single polyprotein precursor comprising only one ORF. The polyprotein is cotranslationally processed by host and virus specific proteases to 10 individual proteins: three structural proteins (capsid (C), premembrane (prM), and envelope (E)) and seven nonstructural (NS) proteins (NS1, 2a, 2b, 3, 4a, 4b, and 5) [2]. The identification and characterization of B-cell epitopes from dengue virus is highly relevant for understanding events related to natural infection, immunopathology, and for vaccines or diagnostic applications. B-cell epitopes have been reported from several dengue virus proteins, the greatest number being derived from E glycoprotein, followed by the nonstructural protein NS1 [3–5]. Although