VMC 221: Veterinary Immunology and Serology (1+1)

PRINCIPLE

• The ability to cause agglutination of erythrocyte of certain species of animals and birds is found in many virus families. This property of haemagglutination is inhibited by the specific antiserum of the virus. If specific antibody and virus are mixed prior to the addition of red blood cells, haemagglutination is inhibited. The Hl test is used either to type antigen or to measure antibody.
• The procedure for the haemagglutination inhibition (Hl) test consists of adding either a standard amount of test serum to dilutions of a virus (Alpha method) or a standard amount of virus to dilutions of the test serum (Beta method). The Beta method is usually followed for estimation of antibody level in a serum sample. Whereas alpha method enables estimation of antigen (virus) during an out break of disease in domestic animals or birds.