Radioimmunoassay for qualitative determination of Antibody to Hepatitis B core antigen (Anti-HBc) 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 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 RIA Tube is an one step competitive radioimmunoassay (RIA) method to measure specific Anti-HBc IgG in human serum or plasma. Negative controls, positive controls and unknown samples are incubated together with 125I-monoclonal anti-HBc antibody in recombinant HBcAg coated tubes. After incubation the contents of the tubes are removed by a washing step and the bound activity is measured in a gamma counter. The concentration of Anti-HBc is reversely proportionated to the radioactivity measured. The values of unknown samples are read off the calibration curve.