Lymphocytes

• Spherical cells, 7-12µm in diameter, large, round nucleus which almost fills the cell, they are mobile and are main cells in lymphoid tissue and specific immune response
• T Lymphocytes mature in the thymus, recognise foreign particles (antigens), help B cells make antibodies (Th) and are important in killing virus-infected cells (Tk); 3 types:

  • CD4^+ Helper T cells (Th cells)
  • CD8^+ killer/cytotoxic T cells (Tk cells)
  • Regulator T cells (Tr cells)
• B Lymphocytes made in bone marrow; can differentiate into plasma cells when made to do so by Th cells (antigen stimulation), also produce antibodies (immunoglobulin)