In this article we will discuss about the structure of antigens with the help of suitable diagrams. Acquired immunity only develops after invasion by a foreign organism or toxin. Each organism or toxin contains at least one special chemical compound that is different from other compounds. In general, these are proteins or large polysaccharides and these compounds initiate acquired immunity. [...]
The following basic properties are known to be essential to make a antigens: 1. Foreign Nature 2. Molecular Size 3. Antigenic Determinants and Cross-Reactivity 4. Molecular Rigidity and Complexity 5. Genetic Factors in the Individual. Property # 1. Foreign Nature: The prerequisite for immunogenicity is that the substance should be foreign to the body of recipient. As a result the [...]
Many clinical tests are being done on the basis of specificity of antibodies for antigen and their ability to recognize epitopes, which is a very small portion or portions of antigen. Antibody based assays are epitope-detecting devices and most of them are based upon the quantitative precipitin curve (Fig. 5.7). A.1 Precipitation reactions in fluids: A quantitative precipitation reaction can [...]