A novel indirect ELISA for diagnosis of dengue fever.
OBJECTIVE
Dengue fever (DF) is associated with significant morbidity and mortality in the tropical and sub-tropical regions of the world. Since there are no effective antiviral drugs for treatment, clinicians often rely on the accurate diagnosis of dengue fever to begin supportive therapy at early stages of the illness. The objective of this study was to develop an in-house dengue virus serotype 2 (DENV-2) non-structural protein- 5 (NS5) based indirect ELISA.


METHODS
DENV-2 was raised in Vero cells and the viral proteins were separated and subsequently the NS5 protein was eluted. Serum samples from primary and secondary dengue fever patients; and acute and convalescent samples from Japanese encephalitis (JE) and West Nile virus (WNV) cases were used to validate the ELISA.


RESULTS
The assay was found to be 100 per cent specific in detecting DENV-2 specific antibodies from patient's serum. However, in terms of sensitivity, the assay could detect IgM antibodies only from 90 per cent of the primary dengue samples. The IgM/IgG ratio of the primary and secondary samples was 7.24 and 0.64, respectively.


CONCLUSIONS
The results indicate that the DENV-2 NS5 ELISA is dengue group specific and can be used to differentiate dengue infection from other circulating Flavivirus infections. This NS5 ELISA can also be used to distinguish between primary and secondary dengue fever on the basis of IgM/IgG ratios. Further studies with larger sample sizes and different DENV serotypes are required to validate the ELISA.
Department of Virology, King Institute of Preventive Medicine & Research, Chennai, India.
Rohan
R
Narayan
Department of Virology, King Institute of Preventive Medicine & Research, Chennai, India.
Senthil
S
Raja
Department of Virology, King Institute of Preventive Medicine & Research, Chennai, India.
Senthil
S
Kumar
Department of Virology, King Institute of Preventive Medicine & Research, Chennai, India.
Mohana
M
Sambasivam
Department of Virology, King Institute of Preventive Medicine & Research, Chennai, India.
Raja
R
Jagadeesan
Department of Virology, King Institute of Preventive Medicine & Research, Chennai, India.
Kavita
K
Arunagiri
Department of Virology, King Institute of Preventive Medicine & Research, Chennai, India.
Kaveri
K
Krishnasamy
Department of Virology, King Institute of Preventive Medicine & Research, Chennai, India.
Gunasekaran
G
Palani
D000818:Animals; D000956:Antigens, Viral / Q000097:blood; D002522:Chlorocebus aethiops; D003715:Dengue / Q000097:blood* / Q000235:genetics / Q000821:virology; D003716:Dengue Virus / Q000302:isolation & purification* / Q000472:pathogenicity; D004672:Encephalitis, Japanese / Q000097:blood / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D014709:Vero Cells / Q000821:virology; D017361:Viral Nonstructural Proteins / Q000097:blood* / Q000235:genetics; D014901:West Nile Fever / Q000097:blood / Q000821:virology; D014902:West Nile virus / Q000235:genetics / Q000302:isolation & purification
D000956:Antigens, Viral; D007074:Immunoglobulin G; D007075:Immunoglobulin M; C582223:NS5 protein, dengue virus; D017361:Viral Nonstructural Proteins