Abstract
Dengue fever and its severe form, dengue hemorrhagic fever (DHF) and dengue shock syndrome are one of the most important mosquito-borne tropical disease. The severe form of dengue disease was hypothesized to be correlated with high viral titer and secondary infection with heterologous serotypes, so called ADE, that caused mostly by anti-Envelop (E) and anti-premembrane (prM) antibodies. However, anti-non-structural 1 (NS1) antibodies was recently interested as one factor for severe dengue infection because of their cross-reactivity with human molecules such as plasminogen, thrombin and endothelial cells, causing some severe symptoms like vascular leakage. However, anti-NS1 antibody was also proved from several studies for their protective activity in vitro and in vivo. To clearly identify the important role of anti-NS1 human antibody, both for dengue pathogenesis and therapeutic, in this study, twelve anti-dengue NS1 human monoclonal antibodies were characterized. Cross-reactivity of those HuMAbs with human molecules, plasminogen, thrombin, and endothelial cell, were determined. Activation of plasmin formation were also investigated. Their viral replication inhibition activity in human microvascular endothelial cell (HMEC-1) were tested in some HuMAbs, which showed and not showed crossreactivity with human molecules. It was shown that all 12 anti-NS1 HuMAbs were cross-reacted with plasminogen, but not with thrombin. Among them, one HuMAbs could not activated plasminogen to plasmin. Some of them showed cross-reactivity with endothelial cell. Fortunately, it was found that one clones that is unable to activate plasminogen, could inhibit viral replication in vitro. Moreover, from epitope mapping with truncated NS1, all anti-HuMAbs were targeted to 301-352 of dengue NS1 protein. This is the first study described the generation and characterization of full IgG human monoclonal antibody specific to NS1 protein of Dengue virus. After thoroughly characterization, the mechanism how anti-NS1 HuMAbs play a role on dengue pathogenesis can be enlighten. Also, the promising role of anti-NS1 as a therapeutic candidates can be shown.
