What Is Antigen presentation.pptx chemistry ppt

bio chemistry presentation / what is antigen

1. What Is Antigen

2. Introduction to Antigens Antigens are molecules that can trigger an immune response in the body. They are typically proteins or polysaccharides found on the surface of pathogens. Antigens can also be found on the surface of normal cells in the body.

3. Types of Antigens There are two main types of antigens: foreign antigens and self-antigens. Foreign antigens come from outside the body, such as bacteria or viruses. Self-antigens are molecules produced by the body's own cells.

4. Antigen Recognition The immune system recognizes antigens using specialized cells called lymphocytes. Lymphocytes have receptors that can bind to specific antigens. When an antigen binds to a lymphocyte, it triggers an immune response.

5. Antigen Presentation Antigens are presented to lymphocytes by antigen-presenting cells (APCs). APCs engulf antigens and display them on their surface. This presentation helps activate lymphocytes and initiate an immune response.

6. Immunogenicity of Antigens Not all antigens are equally immunogenic. Some antigens are highly immunogenic and can trigger a strong immune response. Others are weakly immunogenic and may not elicit a robust response.

7. Antigen Variability Antigens can vary in structure and composition. Pathogens can have different strains with unique antigens. This variability can pose challenges for the immune system in mounting an effective response.

8. Antigen Antibody Interaction When an antigen binds to a lymphocyte, it can stimulate the production of antibodies. Antibodies are proteins that specifically bind to antigens. This binding helps neutralize pathogens and mark them for destruction by other immune cells.

9. Clinical Applications of Antigens Antigens are used in diagnostic tests to detect the presence of specific pathogens. Vaccines contain antigens to stimulate the immune system and provide immunity against diseases. Allergies occur when the immune system reacts to harmless antigens, triggering an allergic response.

10. Summary Antigens are essential for initiating immune responses against pathogens. They can be foreign or self-molecules that are recognized by the immune system. Understanding antigen properties and interactions is crucial for developing vaccines and diagnostic tools.

11. References Abbas, A.K., Lichtman, A.H., & Pillai, S. (2014). Cellular and molecular immunology. Elsevier Health Sciences . Janeway, C.A., Travers, P., Walport, M., & Shlomchik, M.J. (2001). Immunobiology: The immune system in health and disease. Garland Science.