Human Anti-Yellow fever virus Env IgM (YFV Env-IgM) tests is an indirect ELISA suitable for detecting YFV-Env IgM in Human serum or plasma. Other biological fluids, including tissue culture medium, may be validated for user in vitro research use only (RUO), not for therapeutic or diagnostic use.
The microtiter well plate and all other reagents, if unopened, are stable at 2-8°C until the expiration date printed on the box label. Stabilities of the working solutions are indicated under Reagent Preparation.
To Be Reconstituted: Store as indicated.
The YFV-Env antigen coating level, HRP conjugate concentration, and sample Diluent are optimized to differentiate anti-YFV-Env IgG from background (non-antibody) signal with Human serum samples at an appropriate dilution. The positive controls at 100 U/ml represent ~ 100 ng/ml Human IgG. The lowest limit of detection is about 0.3 ng of Human IgG.
Yellow fever is a viral hemorrhagic disease spread between humans, as well as between certain other primates and humans, by the bite of yellow fever-infected mosquitoes. it is spread primarily by mosquitoes of the Aedes aegypti species. The virus is called simply Yellow fever virus (YFV) and belongs to the virus family Flaviviridae. Humans are a dead-end host, terminating the virus's life cycle and consequently suffering from much harsh symptoms than its native host. Yellow fever is a serious, potentially deadly flu-like disease spread by mosquitoes. This disease is most prevalent in tropical and subtropical areas. Yellow fever can't be passed directly from person to person through close contact. According to the recent analysis, there are an estimated 84 000-170 000 cases and up to 60 000 deaths due to yellow fever per year.
Yellow Fever Virus (YFV) is a positive- sense, ssRNA, (11 kb) encoding three structural (C, prM, E) and seven nonstructural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, NS5). Env/E protein is the major inducer and target of virus neutralizing antibodies. The function of the virus E proteins is to attach the virus to receptors on host cells; they initiate the biggest immune response from the host. The M proteins appear to keep the E proteins functional during the assembly of new viruses. C proteins are found in the virus nucleocapsid.
YFV vaccine (killed virus) has been very effective and successful. Chimeric variants of YFV, that express E and prM proteins, are being used to produce vaccines against other arbovirus diseases such as dengue fever (DENV), West Nile (WNV), and Japanese encephalitis (JEV).
YFV Vaccines & Sample Testing
YFV vaccine came into use in 1938. It is on the WHO's List of Essential Medicines. YF-VAX®, Yellow Fever Vaccine, for subcutaneous use, is prepared by culturing the 17D-204 8 strain of yellow fever virus in chicken embryos. YFV vaccination provides life-long immunity and it has>90% efficacy. It has been administered to more than 600 million people worldwide. YF-17D is a live-attenuated vaccine that infects and replicates in target cells, vaccines who receive the YF-17D vaccine usually develop detectable viremia after vaccination. Therefore, antibodies to several structural (Env, prM, capsid) and non-structural proteins NS1-5 may be produced. Antibodies to NS1 are also found in natural infection.
YFV-17D, chimeric variants of YFV are being used to produce vaccines against other arbovirus diseases such as dengue fever (DENV), West Nile (WNV), and Japanese encephalitis (JEV). A new technology, called ChimeriVax has been developed to excise the specific genes that encode the E and prM proteins of the YFV and replace it with the gene for the E and prM protein of the target virus such as DENV. Recombinant RFV-17D chimeic vaccines may retain the NS1 protein so antibodies to NS1 will also be produced.
Serologically, an ELISA during the acute phase of the disease using specific IgM against yellow fever or an increase in specific IgG-titer (compared to an earlier sample) can confirm yellow fever. Together with clinical symptoms, the detection of IgM or a fourfold increase in IgG-titer is considered sufficient indication for yellow fever. Since these tests can cross-react with other flaviviruses, like dengue virus, these indirect methods cannot conclusively prove yellow fever infection. In a differential diagnosis, infections with yellow fever must be distinguished from other feverish illnesses like malaria. Other viral hemorrhagic fevers, such as Ebola virus, Lassa virus, Marburg virus, and Junin virus, must be excluded as cause.
Reconstitution And Storage
Wash Solution Concentrate (50x), 10ml: Dilute the entire volume 10ml + 490 ml with distilled or deionized water into a clean stock bottle. Label as 1X Wash Solution and store at 4°C for long term and ambient temp. for short term.
Sample/HRP Diluent Concentrate (20x), 10ml: Dilute the entire volume, 10ml + 190ml with distilled or deionized water into a clean stock bottle. Label as Working Sample Diluent (WSD) and store at 2-8°C until the kit lot expires or is used up.
Anti-Human IgM- HRP Conjugate Concentrate (100x), 0.11ml: in buffer with detergents and antimicrobial as stabilizers. Dilute fresh as needed; 10ul of concentrate to 1ml of Working Sample Diluent is sufficient for 1 8- well strip. Use within the working day and discard. Return 100X to 2-8°C storage.