1. اختبارات التعادل المناعي:Neutralization Tests:
The neutralization test is an assay based on the ability of antibody to inactivate the biological effects of an antigen or of a microorganism expressing it. Neutralization applies especially to inactivation of virus infectivity or of the biological activity of a microbial toxin.

2. Uses of the neutralization tests :
Recognition of the pathogenic causative agents (Toxins / Viruses) and differentiation between their pathogenicity.
Study the antigenic relation for various toxins and viruses
Detection the biological protection ability of the neutralizing antitoxins and antiviruses against toxins and Viruses .
Measure the potency of vaccines and the ability to induce immunity.

3. Viral Neutralization Tests
Neutralization of a virus is defined as the loss of infectivity through reaction of the virus with specific antibody. Virus and serum are mixed under appropriate condition and then inoculated into cell culture, eggs or animals. The presence of unneutralized virus may be detected by reactions such as CPE, haemadsorption/haemagglutination, plaque formation, disease in animals. The loss of infectivity is caused by interference by of the bound Ab with any one of the steps leading to the release of the viral genome into the host cells.

4. In the complement fixation reaction (Figure 27.30) the
primary union of antigen with antibody takes place almost instantaneously and is invisible. A measured amount of complement present in the reaction mixture is taken up by complexes of antigen and antibody. The consumption or In the complement fixation reaction (Figure 27.30) the
primary union of antigen with antibody takes place almost instantaneously and is invisible. A measured amount of complement present in the reaction mixture is taken up by complexes of antigen and antibody. The consumption or