CIE A Level Biology (9700) 2019-2021

Revision Notes

11.1.4 Antigens

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

Author:

Alistair graduated from Oxford University in 2014 with a degree in Biological Sciences. He has taught GCSE/IGCSE Biology, as well as Biology and Environmental Systems & Societies for the International Baccalaureate Diploma Programme. While teaching in Oxford, Alistair completed his MA Education as Head of Department for Environmental Systems and Societies.
Close

Join Save My Exams

Download all our Revision Notes as PDFs

Try a Free Sample of our revision notes as a printable PDF.

Join Now
Go to Top