Anti-Dengue Envelope Protein monoclonal antibody

The genus Flavivirus in the family Flaviviridae comprises many medically important viruses, such as dengue virus (DENV), Zika virus (ZIKV), and yellow fever virus. The quest for therapeutic targets to combat flavivirus infections requires a better understanding of the kinetics of virus?host interactions during infections with native viral strains. However, this is precluded by limitations of current cell-based systems for monitoring flavivirus infection in living cells. In the present study, we report the construction of fluorescence-activatable sensors to detect the activities of flavivirus NS2B?NS3 serine proteases in living cells. The system consists of GFP-based reporters that become fluorescent upon cleavage by recombinant DENV-2/ZIKV proteases in vitro. A version of this sensor containing the flavivirus internal NS3 cleavage site linker reported the highest fluorescence activation in stably transduced mammalian cells upon DENV-2/ZIKV infection. Moreover, the onset of fluorescence correlated with viral protease activity. A far-red version of this flavivirus sensor had the best signal-to-noise ratio in a fluorescent Dulbecco's plaque assay, leading to the construction of a multireporter platform combining the flavivirus sensor with reporter dyes for detection of chromatin condensation and cell death, enabling studies of viral plaque formation with single-cell resolution. Finally, the application of this platform enabled the study of cell-population kinetics of infection and cell death by DENV-2, ZIKV, and yellow fever virus. We anticipate that future studies of viral infection kinetics with this reporter system will enable basic investigations of virus?host interactions and facilitate future applications in antiviral drug research to manage flavivirus infections.

Background & objectives: In the absence of an effective vaccine or specific antiviral therapy against dengue infection, the only available control measure remains focusing on the incrimination and reduction of vector (mosquito) populations to suppress virus transmission. Diagnosis of dengue in laboratory can be carried out using several approaches, however, their sensitivity and specificity vary from test-to-test. This study was conducted to evaluate the sensitivity and stability of viral envelope (E) and NS1 antigens detected by ELISA in dengue virus infected mosquitoes. Methods: An in-house developed E-ELISA to detect dengue E antigens was first characterized by using cross-reactive monoclonal antibody (mAb) 42-3 and rabbit polyclonal antibodies as the capture and detector antibodies, respectively. The sensitivity of E-ELISA was compared with the Platelia Dengue NS1 Ag kit using experimentally infected or field-caught mosquitoes. Results: Our results demonstrated that the E-ELISA was capable of detecting viral antigens with the sensitivity of 69.57, 100, 52.38 and 66.67% for DENV-1 to DENV-4 infected mosquito pools, respectively. This was comparable to the Platelia Dengue NS1 Ag kit, detecting 100% of DENV-1 infected mosquito pools. Among 124 field-collected mosquito pools collected in the vicinity of localized outbreak areas; both E-ELISA and NS1 Ag kit confirmed nine RT-PCR positive samples with sensitivity and concordance rate up to 100%. Interpretation & conclusion: With the future potential of antigen capture ELISA to be used in the resource deprived regions, the study showed that E-ELISA has similar sensitivity and antigen stability as NS1 Ag kit to complement the current established virological surveillance in human. The improvement of the sensitivity in detecting DENV-3/4 will be needed to incorporate this method into routine mosquito surveillance system.