Development of a humanized antibody with high therapeutic potential against dengue virus type 2

Background: dengue virus (denv) is a significant public health threat in tropical and subtropical regions of the world. a therapeutic antibody against the viral envelope (e) protein represents a promising immunotherapy for disease control. methodology/principal findings: we generated seventeen novel mouse monoclonal antibodies (mabs) with high reactivity against e protein of dengue virus type 2 (denv-2). the mabs were further dissected using recombinant e protein domain i-ii (e-di-ii) and iii (e-diii) of denv-2. using plaque reduction neutralization test (prnt) and mouse protection assay with lethal doses of denv-2,we identified four serotype-specific mabs that had high neutralizing activity against denv-2 infection. of the four,e-diii targeting mab db32-6 was the strongest neutralizing mab against diverse denv-2 strains. using phage display and virus-like particles (vlps) we found that residue k310 in the e-diii a-strand was key to mab db32-6 binding e-diii. we successfully converted db32-6 to a humanized version that retained potency for the neutralization of denv-2 and did not enhance the viral infection. the db32-6 showed therapeutic efficacy against mortality induced by different strains of denv-2 in two mouse models even in post-exposure trials. conclusions/significance: we used novel epitope mapping strategies,by combining phage display with vlps,to identify the important a-strand epitopes with strong neutralizing activity. this study introduced potential therapeutic antibodies that might be capable of providing broad protection against diverse denv-2 infections without enhancing activity in humans. © 2012 li et al.