The only way that one knows that an antigen-antibody reaction has occurred is to have some means of directly or indirectly detecting the complexes formed between the antigen and antibody. The ease with which one can detect antigen-antibody reactions will depend on a number of factors. Many factors influence antigen-antibody reactions. They can be conveniently classified in two groups, according to whether they act on the equilibrium constant or not.
Affinity
The higher the affinity of the antibody
for the antigen, the more stable will be the interaction. Thus, the ease with which one can detect the interaction is enhanced.Avidity
Reactions between multivalent antigens and multivalent antibodies are more stable and thus easier to detect.
Antigen to antibody ratio
The ratio between the antigen and antibody influences the detection of antigen-antibody complexes because the size of the complexes formed is related to the concentration of the antigen and antibody.
Physical form of the antigen
The physical form of the antigen influences how one detects its reaction with an antibody. If the antigen is a particulate, one generally looks for agglutination of the antigen by the antibody. If the antigen is soluble one generally looks for the precipitation of the antigen after the production of large insoluble antigen-antibody complexes.
ANTIGENE-ANTIBODY FORMATION
This defence system is called the specific defence system because the system attacks specific invaders. This can happen by the production of antibodies or by white blood cells engulfing a particular pathogen. White Blood Cells- Lymphocytes and monocytes are produced in the bone marrow. They then are transported by the blood to lymph vessels, lymph nodes, the spleen or the thymus gland.
- Monocytes: These are white blood cells that become macrophages. These are large white blood cells. They engulf invaders. Once engulfed part of the invader remains on the surface of the microphage. This is called an antigen. Antibodies are produced to fight off future invaders.
- Lymphocytes:Some attack body cells that have antigens (parts of the invader) on their surface. Other lymphocytes produce antibodies.Antibodies- Lymphocytes produce antibodies as a result of antigens. These are proteins in the group called immunoglobulins. Each antigen will only stimulate the production of one specific antibody that will fit into its receptor area. This is called naturalactiveinduced immunity. It is protection gained against a particular pathogen by the production of specific antibodies after the antigen on the pathogen has been detected.
No comments:
Post a Comment