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Related to HBeAg: anti-HBe, HBeAb, HBcAg


see immunityimmunity,
ability of an organism to resist disease by identifying and destroying foreign substances or organisms. Although all animals have some immune capabilities, little is known about nonmammalian immunity.
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A substance that initiates and mediates the formation of the corresponding immune body, termed antibody. Antigens can also react with formed antibodies. Antigen-antibody reactions serve as host defenses against microorganisms and other foreign bodies, or are used in laboratory tests for detecting the presence of either antigen or antibody. See Antibody, Antigen-antibody reaction

A protein immunogen (any substance capable of inducing an immune response) is usually composed of a large number of antigenic determinants. Thus, immunizing an animal with a protein results in the formation of a number of antibody molecules with different specificities. The antigenicity of a protein is determined by its sequence of amino acids as well as by its conformation. Antigens may be introduced into an animal by ingestion, inhalation, sometimes by contact with skin, or more regularly by injection into the bloodstream, skin, peritoneum, or other body part.

With a few exceptions, such as the autoantigens and the isoantigens of the blood groups, antigens produce antibody only in species other than the ones from which they are derived. All complete proteins are antigenic, as are many bacterial and other polysaccharides, some nucleic acids, and some lipids. Antigenicity may be modified or abolished by chemical treatments, including degradation or enzymatic digestion; it may be notably increased by the incorporation of antigen into oils or other adjuvants. See Isoantigen

Bacteria, viruses, protozoans, and other microorganisms are important sources of antigens. These may be proteins or polysaccharides derived from the outer surfaces of the cell (capsular antigens), from the cell interior (the somatic or O antigens), or from the flagella (the flagellar or H antigens). Other antigens either are excreted by the cell or are released into the medium during cell death and disruption; these include many enzymes and toxins, of which diphtheria, tetanus, and botulinus toxins are important examples. The presence of antibody to one of these constituent antigens in human or animal sera is presumptive evidence of past or present contact with specific microorganisms, and this finds application in clinical diagnosis and epidemiological surveys. See Botulism, Diphtheria, Toxin

Microbial antigens prepared to induce protective antibodies are termed vaccines. They may consist of either attenuated living or killed whole cells, or extracts of these. Since whole microorganisms are complex structures, vaccines may contain 10 or more distinct antigens, of which generally not more than one or two engender a protective antibody. Examples of these are smallpox vaccine, a living attenuated virus; typhoid vaccine, killed bacterial cells; and diphtheria toxoid, detoxified culture fluid. Several independent vaccines may be mixed to give a combined vaccine, and thus reduce the number of injections necessary for immunization, but such mixing can result in a lesser response to each component of the mixture. See Vaccination

Allergens are antigens that induce allergic states in humans or animals. Examples are preparations from poison ivy, cottonseed, or horse dander, or simple chemicals such as formaldehyde or picryl chloride. See Hypersensitivity, Immunology


A substance which reacts with the products of specific humoral or cellular immunity, even those induced by related heterologous immunogens.


a substance that stimulates the production of antibodies
References in periodicals archive ?
Compound 4, 6,7,8 showed selective inhibition on HBeAg and no activity on HBsAg, while compound 13 selectively inhibited HBsAg secretion.
Positivity for HBeAg ana presence of detectable HBV DNA in the serum also showed seasonal variations, with a peak at the transition during periods of high and low AF[B.
In either case, the presence of HBeAb indicates a low level of viral replication with low to moderate infectivity, while HBeAg indicates high viral replication and infectivity.
Attainment of HBeAg or HBsAg seroconversion with therapy is rarely seen, especially in HIV-infected individuals, given the stability of the cccDNA reservoir within infected hepatocytes.
This study investigated the continuing use in the United Kingdom of maternal HBeAg markers as predicators for enhanced neonatal HBIg prophylaxis in addition to neonatal vaccine.
We then studied the interference between the 2 antibody pairs and noticed that the capture antibody EB3 used in the single assay of HBeAg had strong nonspecific binding to the detection antibody S04 for the HBsAg assay, resulting in high background signals in the HBsAg detection.
In addition, HBV vaccination administered after negativation of serum HBV DNA on treatment with lamivudine did not prevent viral multiplication relapse and did not induce HBeAg seroconversion.
HBeAg positivity was significantly more common in HIV-infected than in HIV-uninfected women (p=0.
If HBeAg is positive, and/or ALT is more than twice the upper limit of normal, the patient should be referred for tenofovir plus lamivudine or emtricitabine-based antiretroviral therapy (ART), as above.
Kaplan-Meier estimates and log-rank analyses were used to identify factors associated with the time to HBeAg seroconversion and test for the comparison of median values of two independent groups.
This phase may last for several weeks to years and if successful, HBeAg seroconversion will occur with the development of sustained HBe-antibody titres.
After 8 days of treatment, culture medium was collected and HBsAg and HBeAg were determined by radiommunoassay, according to the manufacturer's protocol.