If you have to detect any patient is suffering from HIV or not, which procedure of AgAb reaction will be followed among above and how?

Question

The presence of antibody in serum is not always because of exposure to antigenic stimulus by red cells. Some foreign substances like bacteria and plants (containing red cell like substances) can cause antibody production and these antibodies are called naturally occurring antibodies. These are commonly of IgM type, occur in serum without any specific antigenic stimulus, e.g., anti-A, anti-B, and anti- Wra. These antibodies are present in individuals who lack that antigen. Immune antibodies are IgG. They develop due to immunization following pregnancy, previous transfusion, or deliberate injection of immunogenic material. In some instances, immunogenic event is unknown. 

The antigen-antibody reactions In-vitro 

1. Agglutination 

2. Hemolysis 

3. Precipitation 

4. Enzyme linked immunosorbent assay (ELISA) 

(a) If you have to detect any patient is suffering from HIV or not, which procedure of AgAb reaction will be followed among above and how? 

(b) What is the difference between Agglutination and Hemolysis?

Answer 1

To detect the presence of HIV in human body, ELISA is used. Here an enzyme label is used and a color reaction that takes place in presence of a substrate denotes the presence of antigen/ antibody. This is the principle sued in Transfusion transmitted disease tests. 

1. Agglutination: 

It is defined as clumping of particles that have antigen on their surface and is brought about by anti-bodies. This forms the basis of blood grouping tests. 

2. Hemolysis: 

Rupture of red cells with release of intracellular hemoglobin can occur if the Antibody has the property of hemolysin. It requires presence of complement.