Dengue virus IgG
Enzyme ImmunoAssay (ELISA) for the qualitative/semiquantitative determination of IgG antibodies to Dengue virus subtypes 1,2,3 & 4 in human plasma and sera. The product is intended mostly for the follow-up of Dengue virus infection.
Dengue virus is a member of the virus family Flaviviridae and is transmitted to people through the bite of the mosquitos Aedes aegypti and Aedes albopictus. Each year, 100 million people become infected with dengue virus. However, the majority of deaths that result from dengue infection result from Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS). The incubation period of dengue fever is approximately four days. It is difficult to distinguish dengue fever from other viral diseases and the person usually recovers in 5 days. DHF has a similar incubation period as dengue fever and many of the same symptoms. However, the fever is more severe and the drowsiness and lethargy is more extreme. This can cause the individual to loose blood volume, result in hypotension, go into shock (DSS) and die. It is important to understand why an individual will develop DHF/DSS. The Dengue virus has been shown to have 4 subtypes. These 4 subtypes are different strains of dengue virus that have 60-80% homology between each other. After a person is infected with dengue, they develop an immune response to that dengue subtype. The immune response produced specific antibodies to that subtype’s surface proteins that prevents the virus from binding to macrophage cells (the target cell that dengue viruses infect) and gaining entry. However, if another subtype of dengue virus infects the individual, the virus will activate the immune system to attack it as if it was the first subtype. The immune system is tricked because the 4 subtypes have very similar surface antigens. The antibodies bind to the surface proteins but do not inactivate the virus. The immune response attracts numerous macrophages, which the virus proceeds to infect because it has not been inactivated. This situation is referred to as Antibody-Dependent Enhancement (ADE) of a viral infection. This makes the viral infection much more acute. The body releases cytokines that cause the endothelial tissue to become permeable which results in hemorrhagic fever and fluid loss from the blood vessels.
Microplates are coated with an highly purified immunodominant Dengue virus antigen. In the 1st incubation, the solid phase is treated with diluted samples and anti Dengue virus IgG are captured, if present, by the antigens.
After washing out all the other components of the sample, in the 2nd incubation bound anti Dengue virus IgG are detected by the addition of anti hIgG antibody, labeled with peroxidase (HRP). The enzyme captured on the solid phase, acting on the substrate/chromogen mixture, generates an optical signal that is proportional to the amount of anti Dengue virus IgG antibodies present in the sample.
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