Ting Zhang - Recombinant DENV 2 NS5: An Effective Antigen for Diagnosis of Dengue  Infection
Channel: Institut des Hautes Études Scientifiques (IHÉS)
Date: 2018-03-27

Dengue fever as one of the most important mosquito-borne disease worldwide which approximately  half  of  the  world's  population  is  at  risk  presenting  several  degrees  of symptoms,  including  life-threatening dengue  haemorrhagic fever (DHF) and 
dengue shock syndrome (DSS). 
Dengue virus (DENV) belongs to the Flaviviridae family, and are  classified  into  four  immunologically  distinct  serotypes,  DENV  1  to  4. Although, there is no specific treatment, early diagnosis is important for proper medical care to minimize mortality, and for prompt initiation of public health control measures. 
There are some diagnostic tests targeting NS1 antigen in commercial, but these methods need all  the  four  serotypes  of  NS1.  NS1  and  NS5  are  translated  and  appear  almost 
simultaneously. 
Our work is mainly based on the fact that NS5 is the most
conservative protein among all  the  flavivirus family,  and its’ RNA
dependent  RNA  polymerase (RdRp) domain plays  a  vital  role 
in viral  RNA  replication. Itis  a prospective biomarker for  dengue 
infection. In this study, we constructed the DENV 2 NS5 full length
and DENV2 NS5 C-terminus RdRp domain (NS5-C70) expression plasmids, a 104 kDa fragment of NS5, and a 70 kDa fragment of 
NS5-C70 were respectively expressed in Escherichia coli.
These two  purified recombinant  products reacted  with sera  of  patients  infected  with dengue virus in  an  enzyme-linked  immunosorbent  assay with significantly higher optical density
values compared with the control sera.  The recombinant DENV 2 NS5 showed strong reactivity  for any  of  the four  serotypes, while 
the  NS5-C70 fragment showed strong reactivity for DENV 2 and 4. 
It is suggested DENV 2 NS5 can detect all the four serotypes patients, greatly reducing the cumbersome procedures with four viral types of antigens in early diagnostic process. The recombinant NS5 protein might be an effective antigen for dengue diagnosis, and NS5-C70 also can be used for auxiliary diagnosis.