AQA A Level Biology

Revision Notes

2.5.6 The Role of Helper T cells

The Role of Helper T cells

  • Activated T-lymphocytes (those that have receptors specific to an antigen) divide by mitosis to increase in number (similar to the clonal selection and clonal expansion of B-lymphocytes)
  • These T-lymphocytes differentiate into two main types of T cell:
    • helper T cells
    • cytotoxic (killer) T cells
  • Helper T cells assist other white blood cells in the immune response
  • They release cytokines (hormone-like signals) which stimulate:
    • The maturation of B-lymphocytes into antibody-secreting plasma cells
    • The production of memory B cells
    • The activation of cytotoxic T cells, which destroy virus infected cells and tumour cells
    • An increased rate of phagocytosis

The function of T-lymphocytes during an immune response, downloadable AS & A Level Biology revision notes

Helper T cells and killer T cells carry out different functions during an immune response


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.

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