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(1) the period that elapses during HBsAg to HBsAb seroconversion, i.e. between the disappearance of surface antigen (HBsAg) from serum and the appearance of HBsAb (anti-HBs), and (2) the period between infection and appearance of HBsAg. During the window of HBsAg to HBsAb seroconversion, IgM anti-core (HBc-IgM) is the only detectable antibody.
The time between the removal of the HBsAg and the appearance of anti-HBs is called the window period. A person negative for HBsAg but positive for anti-HBs either has cleared an infection or has been vaccinated previously. Individuals who remain HBsAg positive for at least six months are considered to be hepatitis B carriers. [68]
The window period for HBsAg/anti-HBs testing occurs as concentration of HBsAg falls and before the body develops anti-HBs antibodies, lasting approximately six to eight weeks in most individuals. [66] During this time, serology assays can test for total anti-HBc. [60]
HBeAg is produced by proteolytic processing of the pre-core protein. The DNA polymerase is encoded by gene P. Gene S is the gene that codes for the surface antigen (HBsAg). The HBsAg gene is one long open reading frame but contains three in frame "start" (ATG) codons that divide the gene into three sections, pre-S1, pre-S2, and S. Because of ...
The HBV has four genes: S, P, C, and X. The S gene codes for the "major" envelope protein (HBsAg). The largest gene is P. It codes for DNA polymerase. The C gene codes for HBeAg and HBcAg. The C gene has a precore and a core region. If translation is initiated at the precore region, the protein product is HBeAg.
The genome organisation of HBV; the genes overlap. ORF S, in green, encodes HBsAg. HBsAg under a transmission electron microscope: the protein self assembles into virus-like particles. HBsAg (also known as the Australia antigen) is the surface antigen of the hepatitis B virus (HBV). Its presence in blood indicates existing hepatitis B infection.
The Hepatitis B virus (HBV) polymerase is a multifunctional enzyme, with both RNA-dependent and DNA-dependent polymerase functions, as well as an RNase H function. It acts on the HBV pre-genomic RNA (pgRNA) to reverse transcribe it to form a new rcDNA molecule within a new capsid.
HBIG should be given within 14 days of exposure to the hepatitis B virus. [7] The half-life of HBIG is about 3 weeks. In lieu of a booster administration of HBIG, a hepatitis B vaccination is initiated at the time of the initial HBIG administration, thus providing long term protection.