HBsAg (also known as the Australia antigen) is the surface antigen of the hepatitis B virus (HBV). It indicates current hepatitis B infection.
The viral envelope of an enveloped virus has different surface proteins from the rest of the virus which act as antigens. These antigens are recognized by antibody proteins that bind specifically to one of these surface proteins.
Today, these antigen-proteins can be genetically manufactured (e.g. transgene E. coli ) to produce material for a simple antigen test, which detects the presence of HBV.
It is present in the sera of patients with viral hepatitis B (with or without clinical symptoms). Patients who developed antibodies against HBsAg (anti-HBsAg seroconversion) are usually considered non-infectious. HBsAg detection by immunoassay is used in blood screening, to establish a diagnosis of hepatitis B infection in the clinical setting (in combination with other disease markers) and to monitor antiviral treatment.
In histopathology, the presence of HBsAg is more commonly demonstrated by the use of the Shikata orcein technique, which uses a natural dye to bind to the antigen in infected liver cells.
Positive HBsAg tests can be due to recent vaccination against Hepatitis B virus but this positivity is unlikely to persist beyond 14 days post-vaccination.
It is commonly referred to as the Australia Antigen. This is because it was first isolated by the American research physician and Nobel Prize winner Baruch S. Blumberg in the serum of an Australian Aboriginal person.It was discovered to be part of the virus that caused serum hepatitis by virologist Alfred Prince in 1968.
Heptavax, a "first-generation" hepatitis B vaccine in the 1980s, was made from HBsAg extracted from the blood plasma of hepatitis patients. Current vaccines are made from recombinant HBsAg grown in yeast.
Hepatitis is inflammation of the liver tissue. Some people with hepatitis have no symptoms, whereas others develop yellow discoloration of the skin and whites of the eyes (jaundice), poor appetite, vomiting, tiredness, abdominal pain, and diarrhea. Hepatitis is acute if it resolves within six months, and chronic if it lasts longer than six months. Acute hepatitis can resolve on its own, progress to chronic hepatitis, or (rarely) result in acute liver failure. Chronic hepatitis may progress to scarring of the liver (cirrhosis), liver failure, and liver cancer.
DNA vaccination is a technique for protecting against disease by injection with genetically engineered plasmid containing the DNA sequence encoding the antigen(s) against which an immune response is sought so cells directly produce an antibody, producing a protective immunological response. DNA vaccines have potential advantages over conventional vaccines, including the ability to induce a wider range of immune response types.
Hepatitis D is a disease caused by the hepatitis delta virus (HDV), a small spherical enveloped virusoid. This is one of five known hepatitis viruses: A, B, C, D, and E. HDV is considered to be a subviral satellite because it can propagate only in the presence of the hepatitis B virus (HBV). Transmission of HDV can occur either via simultaneous infection with HBV (coinfection) or superimposed on chronic hepatitis B or hepatitis B carrier state (superinfection).
Hepadnaviridae is a family of viruses. Humans, apes, and birds serve as natural hosts. It is a family of viruses that has the smallest genome among animal DNA viruses. There are currently 18 species in this family, divided among 5 genera. Its best-known member is hepatitis B virus. Diseases associated with this family include: liver infections, such as hepatitis, hepatocellular carcinomas, and cirrhosis. Hepadnaviruses have some similar features with the retrovirus family: a) Hepatitis B virus uses the reverse transcriptase enzyme to convert DNA into RNA, just like retroviruses. b) The function of gag, pol and env genes in retroviruses is the same as C, P and S genes in Hepadnaviruses. c) Both are enveloped viruses.
Virus-like particles (VLPs) are molecules that closely resemble viruses, but are non-infectious because they contain no viral genetic material. They can be naturally occurring or synthesized through the individual expression of viral structural proteins, which can then self assemble into the virus-like structure. Combinations of structural capsid proteins from different viruses can be used to create recombinant VLPs. VLPs derived from the Hepatitis B virus (HBV) and composed of the small HBV derived surface antigen (HBsAg) were described in 1968 from patient sera. VLPs have been produced from components of a wide variety of virus families including Parvoviridae, Retroviridae, Flaviviridae, Paramyxoviridae and bacteriophages. VLPs can be produced in multiple cell culture systems including bacteria, mammalian cell lines, insect cell lines, yeast and plant cells.
The Jade Ribbon Campaign (JRC) was launched by the Asian Liver Center (ALC) at Stanford University in May 2001 during Asian Pacific American Heritage Month to help spread awareness internationally about hepatitis B (HBV) and liver cancer in Asian and Pacific Islander (API) communities.
A breakthrough infection is a case of illness in which a vaccinated individual becomes sick from the same illness that the vaccine is meant to prevent. Simply, they occur when vaccines fail to provide immunity against the pathogen they are designed to target. Breakthrough infections have been identified in individuals immunized against a variety of different diseases including Mumps, Varicella, and Influenza. The character of breakthrough infections is dependent on the virus itself. Often, the infection in the vaccinated individual results in milder symptoms and is of a shorter duration than if the infection was contracted naturally.
Hepatitis B vaccine is a vaccine that prevents hepatitis B. The first dose is recommended within 24 hours of birth with either two or three more doses given after that. This includes those with poor immune function such as from HIV/AIDS and those born premature. It is also recommended that health-care workers be vaccinated. In healthy people routine immunization results in more than 95% of people being protected.
Cancer immunoprevention is the prevention of cancer onset with immunological means such as vaccines, immunostimulators or antibodies. Cancer immunoprevention is conceptually different from cancer immunotherapy, which aims at stimulating immunity in patients only after tumor onset, however the same immunological means can be used both in immunoprevention and in immunotherapy.
Hepatitis B is an infectious disease caused by the hepatitis B virus (HBV) that affects the liver. It can cause both acute and chronic infection. Many people have no symptoms during the initial infection. In acute infection, some may develop a rapid onset of sickness with vomiting, yellowish skin, tiredness, dark urine and abdominal pain. Often these symptoms last a few weeks and rarely does the initial infection result in death. It may take 30 to 180 days for symptoms to begin. In those who get infected around the time of birth 90% develop chronic hepatitis B while less than 10% of those infected after the age of five do. Most of those with chronic disease have no symptoms; however, cirrhosis and liver cancer may eventually develop. Cirrhosis or liver cancer occur in about 25% of those with chronic disease.
HBcAg is a hepatitis B viral protein. It is an indicator of active viral replication; this means the person infected with Hepatitis B can likely transmit the virus on to another person.
The 2009 Gujarat hepatitis B outbreak was a cluster of hepatitis B cases that appeared in Modasa, northern Gujarat, India in 2009. Over 125 people were infected and up to 49 people died. Several doctors were investigated and arrested after the outbreaks.
Hepatitis B virus (HBV), is a partially double-stranded DNA virus, a species of the genus Orthohepadnavirus and a member of the Hepadnaviridae family of viruses. This virus causes the disease hepatitis B.
A neutralizing antibody (NAb) is an antibody that defends a cell from a pathogen or infectious particle by neutralizing any effect it has biologically. Neutralisation renders the particle no longer infectious or pathogenic. Neutralizing antibodies are part of the humoral response of the adaptive immune system against viruses, intracellular bacteria and microbial toxin. By binding specifically to surface structures (antigen) on an infectious particle, neutralizing antibodies prevent the particle from interacting with its host cells it might infect and destroy. Immunity due to neutralising antibodies is also known as sterilizing immunity, as the immune system eliminated the infectious particle before any infection took place.
A precore mutant is a variety of hepatitis B virus that does not produce hepatitis B virus e antigen (HBeAg). These mutants are important because infections caused by these viruses are difficult to treat, and can cause infections of prolonged duration and with a higher risk of liver cirrhosis. The mutations are changes in DNA bases from guanine to adenine at base position 1896 (G1896A), and from cytosine to thymine at position 1858 (C1858T) in the precore region of the viral genome.
Vaccine-induced seropositivity (VISP) is the phenomenon wherein a person who has received a vaccine against a disease would thereafter give a positive or reactive test result for having that disease when tested for it, despite not actually having the disease. This happens because many vaccines encourage the body to produce antibodies against a particular disease, and blood tests often determine whether a person has those antibodies, regardless of whether they came from the infection or just a vaccination.
David Maurice Surrey Dane, MRCS CRCP MB Bchir MRCP MRCPath FRCPath FRCP was a pre-eminent British pathologist and clinical virologist known for his pioneering work in infectious diseases including poliomyelitis and the early investigations into the efficacy of a number of vaccines. He is particularly remembered for his strategic foresight in the field of blood transfusion microbiology, particularly in relation to diseases that are spread through blood transfusion.
Ground squirrel hepatitis virus, abbreviated GSHV, is a partially double-stranded DNA virus that is closely related to human Hepatitis B virus
The woolly monkey hepatitis B virus (WMHBV) is a viral species of the Orthohepadnavirus genus of the Hepadnaviridae family. Its natural host is the woolly monkey (Lagothrix), an inhabitant of South America categorized as a New World primate. WMHBV, like other hepatitis viruses, infects the hepatocytes, or liver cells, of its host organism. It can cause hepatitis, liver necrosis, cirrhosis, and hepatocellular carcinoma. Because nearly all species of Lagothrix are threatened or endangered, researching and developing a vaccine and/or treatment for WMHBV is important for the protection of the whole woolly monkey genus.
The epidemiology of hepatitis D occurs worldwide. Although the figures are disputed, a recent systematic review suggests that up to 60 million individuals could be infected. The major victims are the carriers of the hepatitis B surface antigen (HBsAg), who become superinfected by the HDV, and intravenous drug users who are the group at highest risk. The infection usually results in liver damage ; this is most often a chronic and severe hepatitis rapidly conducive to cirrhosis.