summary of the processes of immunity

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  • type of white blood cell
  • travel in blood
  • non-specific                                          

1. phagocyte is attracted to the pathogen by chemoattractants - moves down a concentration gradient

2. the phagocyte binds to the pathogen

3. phagocyte engulfs pathogen = phagosome - lysosome moves towards it

4. lysosome releases lytic enzymes into phagosome - break down the pathogen by hydrolysis

5. break down products are absorbed by the phagocyte  

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Type of white blood cell
Specific immune response

T Lymphocytes: (T-Cells)
1. Produced in Bone Marrow
2. Cell-mediated Immunity
3. Matured in Thymus Gland
4. Responds to foreign material inside body cells
5. Responds to own cells altered by viruses, cancer and transplanted tissue

B Lymphocytes: (B-Cells)
1. Produced & Matured in Bone Marrow
2. Humoral Immunity
3. Produces Antobodies
4. Responds to foreign material outside body cells (in body fluids/humour)
5. Responds to bacteria and viruses

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Cell-Mediated Immunity

1. Pathogen invades body cell/ is taken in by phagocytosis

2. Phagocyte/cell places anitgens from the pathogen on its surface (as a sign of distress)

3. Receptors on T helper Cells fit onto these antigens

4. This activates other T cells to divide by mitosis to form clones

5. The cloned T cells:

  • Develop into memory cells
  • Stimulate phagocytes
  • Stimulate B cells (T killer cells produce protein to make holes in cell membrane)
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Humoral Immunity

1. The surface antigens of invading pathogens are taken up by B cells

2. B cells process and present the pathogens antigens

3. T helper cells attach to the anitgens on the B cells and therefore activate them to divide by mitosis - produces plasma cells and memory cells

4. Cloned plasma cells produce anitbodies that fit the antigens on the pathogens surface

5. Antibodies attach to antigens and destroy them = primary immune response

6.  Memory Cells respond to future infections by dividing rapidly and producing plasma cells and more memory cells = secondary immune response

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Antibodies = proteins synthesised by B cells


  • 4 Polypeptide Chains - 2 are long = 2 heavy chains - 2 are short = 2 light chains
  • Constant Region = inbetween heavy chains, same on every antibody, where receptors bind
  • Variable Region = inbetween light chains, different on each antibody, where the antigen binds (to form antigen-antibody complex), made of a sequence of amino acids specific to that antibody

Monoclonal Antibodies:

when a specific antibody is isolated and cloned outside of the body
used: pregnancy tests, drugs tests, cancer treatment, transplant surgery

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What exam board is this for,could you please tag it to that exam board,thanks :)

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