Immunoradiometric assay for qualitative determination of IgM Antibody to Hepatitis B core antigen (Anti-HBc IgM) in human serum or plasma
In 1965, Dr. Blumberg who was studying hemophilia, found an antibody in two patients which reacted against an antigen from an Australian Aborigine. Later the antigen was found in patients with serum type hepatitis and was initially designated "Australian Antigen". Subsequent study has shown the Australian Antigen to be the hepatitis B surface antigen (HBsAg, HBs Antigen). Initially there appeared to be three particles associated with hepatitis B infection: a large "complete" particle called the "Dane particle", a small circular 22 nm particle and an oblong 42 nm C particle. Further research identified the Dane particle as the hepatitis B virion and the other two particles as excess surface protein. This former terminology is no longer used and the virus is referred to according to its structure.
Subsequent association with hepatitis B virus (HBV) led to the development of sensitive, specific markers of HBV infection. During acute and chronic HBV infection, HBsAg is produced in excess amounts, circulating in blood as both 22 nm spherical and tubular particles. HBsAg can be identified in serum 30~60 days after exposure to HBV and persists for variable periods depending on the resolution of the infection. Antibody to HBsAg (anti-HBs) develops after a resolved infection and is responsible for long-term immunity. Anti-HBc IgM develops in both resolved acute infections and chronic HBV infections and persists indefinitely. Immunoglobulin M (IgM) anti-HBc appears early in infection and persists for greater than or equal to 6 months. It is a reliable marker of acute HBV infection.
** Modes of Transmission: Transmission of HBV occurs via percutaneous or permucosal routes, and infective blood or body fluids can be introduced at birth, through sexual contact or by contaminated needles. Infection can also occur in settings of continuous close personal contact (such as in households or among persons in institutions for the developmentally disables), presumably via inapparent or unnoticed contact of infective secretions with skin lesions or mucosal surfaces.
The RIAKEY Anti-HBc IgM IRMA Tube is two step non-competitive immunoradiometric (IRMA) method (‘‘sandwich’’) to measure specific Anti-HBc IgM in human serum or plasma. In the first incubation, Anti-HBc IgM in the samples and controls are captured on tubes coated with monoclonal Anti-human IgM antibody. In the second incubation, Recombinant HBcAg combines with a Ag-Ab complex and 125I-labeled monoclonal Anti-HBc IgG are added to react. At the end of each incubation, the unbound materials are removed by aspiration and washing. The amount of bound tracer will be directly proportional to the Anti-HBc IgM concentration and the remaining radioactivity bound to the tubes is measured in a gamma scintillation counter.