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
- 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
- T killer cells
- T killer cells patrol the body in search of antigen-presenting body cells
- T killer cells attach to the foreign antigens on the cell surface membranes of infected cells and secrete toxic substances that kill the infected body cells, along with the pathogen inside
- Perforins secreted by T killer cells punch a hole in the cell surface membrane of infected cells, allowing toxins to enter
- Helper T cells
Helper T cells and killer T cells carry out different functions during an immune response
