lymphoctes

• •Are involved in the body’s immune response to destroy a pathogen • All lymphocytes have a large nucleus and can give a person immunological memory • There are two main types of lymphocyte: T lymphocytes and B lymphocytes 
• T lymphocytes

  HELPER T lymphocyte can send chemical signals to the B lymphocyte stimulating the B cell to divide by mitosis.Other types of T lymphocytes can directly destroy cancer cells in the body or directly destroy cells infected by a virus
• Vaccines

  • Vaccine contains weakened pathogen
  • T lymphocyte recognises pathogen and activates b lymphocytes
  • B lymphocytes divide by mitosis to produce plasma cells and memory cells
  • Plasma cells release antibodies
  • Memory cells remain in circulation to respond to future reinfection faster