Antigens, Self & Non-Self
- Every cell in the human body has markers that identify it
- Microorganisms (both pathogenic and non-pathogenic), such as bacteria and viruses, also have their own unique markers
- These markers are called antigens (which are macromolecules) and they allow cell-to-cell recognition
- Antigens are found on cell surface membranes, bacterial cell walls, or the surfaces of viruses
- Some glycolipids and glycoproteins on the outer surface of cell surface membranes act as antigens
- Antigens can be either self antigens or non-self antigens:
- Antigens produced by the organism's own body cells (those that the immune system does not recognise as foreign antigens) are known as self antigens
- Self antigens do not stimulate an immune response
- Antigens not produced by the organism’s own body cells (those that the immune system recognises as being foreign eg. the antigens found on pathogenic bacteria and viruses or if a person receives a different blood type during a transfusion) are known as non-self antigens
- Non-self antigens stimulate an immune response
