Neutralization Tests (Immunology)

Neutralization test

When a neutralizing antibody defends a cell from an antigen or infectious body by inhibiting or neutralizing any biological effect, it is termed “neutralization”. The antibody response is crucial for preventing many viral infections and may also contribute to the resolution of an infection.

When a vertebrate is infected with a virus, antibodies are produced against many epitopes of multiple virus proteins. A subset of these antibodies can block viral infection by a process called neutralization. This usually involves formation of a virus-antibody complex.

Neutralization tests are performed in vitro at cellular level including cells in the form of organs and at sub-cellular level. They assess efficacy of antibody fragments, or antibodies, to inhibit critical stages of activities which are generally deleterious to humans. These tests mostly employed to viruses and toxins. Thus, neutralization are of two types:

  1. Virus Neutralization test.
  2. Toxin Neutralization test.


Virus neutralization tests are serological tests to detect presence and magnitude of functional systemic antibodies (Monoclonal and polyclonal) that prevent infectivity of a virus. E.g. viral hemagglutination inhibition test.

Toxin neutralization tests are based on the principle that biological action of toxin is neutralized on reacting with specific neutralizing antibodies called antitoxins. E.g. Nagler reaction used for rapid detection of Clostridium welchii.


Neutralization Tests


Recently, potent and broadly neutralizing human antibodies against influenza have been reported, and have suggested possible strategies to generate an improved vaccine that would confer long-lasting immunity. Another disease which has been linked to the production of neutralizing antibodies is multiple sclerosis.

Neutralizing antibodies have shown potential in treatment of retroviral infections. Medical researchers have shown how encoding of genes which influence the production of particular type of antibody could help in the treatment of infections that attack the immune system. Experts in the field have used HIV treatment as an example of infections these antibodies can treat.


In diagnostic immunology and virology laboratories, evaluation of neutralizing antibodies, which destroy the infectivity of viruses, can be measured by neutralization method.


In this test, patient serum is mixed with a suspension of infectious virus particles of same type as those suspected of causing disease in the patient. A control suspension of virus is mixed with normal serum and is then inoculated into an appropriate cell culture. If the patient serum contains antibody to the virus, antibody will bind virus particles and prevent them from invading the cells in culture, thereby neutralizing infectivity of virus. This technique is labor-intensive, demanding, and time consuming. It application is restricted to laboratories that perform routine viral cultures and related diagnosis.


Download Link: Neutralization Tests.pdf

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