Heterophilic Blocking Reagent

Heterophilic Blocking Reagent，Antibody blocker, Active blocker, HBR

Heterophilic antibodies

Heterophilic antibody (HA) first refers to a class of antibodies that can agglutinate sheep red blood cells in patients with infectious mononucleosis infected by Epstein-Barr virus (Epstein-Barr virus). It is called "heterologous affinity", and later refers to the unexplained polyspecific, low affinity antibody. A class of antibodies that interact with a variety of immune substances. The researchers found that the heterophilic antibody had a molecular weight of 150KD, comparable to that of IgG. Heterotropic antibodies are produced for a variety of reasons, including the use of murine antibodies, vaccination, exposure to certain animals, bacterial infections, and autoimmune diseases.

Heterotropic antibodies are traditionally divided into ① human anti-animal antibody (HAAA), of which human anti-mouse antibody (HAMA) is the most important. (2) Unknown causes of heterotropic antibodies, these antibodies do not have a clear history of antigen contact, but have a wide affinity with animal-derived antibodies. (3) Rheumatoid factor with cross reaction, rheumatoid factor refers to the antibody that can bind its own IgG molecule Fc fragment, because the Fc fragment of human IgG antibody and the Fc part of animal IgG sequence have homology, so some rheumatoid factors have cross reaction ability, combined with animal-derived antibody.

Principle of heterophilic antibody interference

In the double-antibody sandwich immunoassay, at least two antibodies against different epitopes of the antigen, the capture antibody and the marker antibody, are used. They can be derived from monoclonal or polycolon antibodies of the same species or different species. The capture antibody is coated in the solid phase and the labeled antibody is free in the solution. Under normal circumstances, when the tested substance forms an immune sandwich complex with the two antibodies, the signal labeled on the secondary antibody can be displayed, and the signal is linear with the amount of the substance to be tested. When heterotropic antibodies are present, these antibodies can link the two test antibodies, mimicking the behavior of the object to be tested, resulting in false positives. In addition, when there are too many heterophilic antibodies, Hook effect will occur, that is, too many heterophilic antibodies bind to capture antibody and marker antibody respectively, but cannot generate immune complexes, resulting in false negative results.

blockers

blocker is a class of materials that can be used in the development of in vitro diagnostic reagents to reduce protein interference from patient samples or other factors in the test process, which may cause false positive and false negative false test results.

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Passive blocking agent (HAAA blocking agent), human anti-animal antibody blocking agent, that is, animal IgG or anti-serum from rat, rabbit, sheep, cow, etc. Passive blockers usually block only one type of distractor.

An active blocker (heterophilic antibody blocker) is a specific component that targets all heterophilic antibody interference, including HAAA and RF. Once bound to the interfering antibody, steric hindrance is produced by binding to the interfering substance to further prevent the interfering substance from binding to the assay substance. In practice, the concentration of active blockers is usually lower than that of passive blockers, which can reduce the negative effects of excessive use of passive blockers, such as reduced detection signal.

Abgree has a large supply of heterotropic antibody blockers, which can effectively avoid false positives and false negatives, and are widely used in immunochromatography and chemiluminescence platforms