Medicine & USMLE

Types of Activated T-Cells

  1. Innate Immunity
  2. Adaptive Immunity
  3. Macrophages
  4. Neutrophils
  5. Dendritic Cells
  6. Mast Cells
  7. Eosinophils
  8. Basophils
  9. Natural Killer Cells
  10. Antigens
  11. MHC I and II
  12. Antibodies
  13. B Lymphocytes Overview
  14. B Cell Stages
  15. B-Cell Activation
  16. Plasma B-Cells
  17. Memory B-Cells
  18. T-Lymphocytes Overview
  19. T-Cell Stages
  20. Types of Activated T-Cells


After binding to antigens, T-cells are activated as one of three different cell types: helper, cytotoxic, and memory T-cells. Helper T-cells help coordinate the immune response by activating other cell types, like B-cells, cytotoxic T-cells, and the general responders of the innate immune system. Cytotoxic T-cells directly kill pathogens or infected cells by releasing perforin. Finally, memory T-cells retain information about the pathogen so our system can coordinate a stronger secondary response in the case of another infection by the same pathogen.

Key Points

  • Types of Activated T-cells
    • Activation (antigen-binding) produces 3 types of mature T cells
      • Helper T cells 
        • “Help” the immune response by activating other cells and coordinating a response
      • Cytotoxic/killer T cells 
        • Directly kill pathogens/infected cells by releasing perforin, a protein which punctures the antigen-carrying cell
      • Memory T cells
        • Store information (memory) about specific pathogen to prepare for secondary response 
      • T regulatory cells: help reduce autoimmune diseases by distinguishing b/w self and nonself molecules