Medicine & USMLE


  1. TNF-alpha
  2. IL-1
  3. IL-2
  4. IL-3
  5. IL-4
  6. IL-5
  7. IL-6
  8. IL-8
  9. IL-10
  10. IL-12
  11. TGF-beta
  12. IFN-alpha and IFN-beta
  13. IFN-gamma


Interleukin 2 (IL-2) is a cytokine produced mainly by Helper T-cells. IL-2 helps amplify the immune response by stimulating the growth of all lymphocytes, including T-cells, B-cells, and NK cells. Due to its stimulation of NK cells, IL-2 signalling has anti-tumor effects (NK cells attack tumors), which are harnessed by IL-2 analogues like aldesleukin. IL-2 production is dependent on calcineurin, which is targeted by the immunosuppressive drugs cyclosporine and tacrolimus.

Key Points

  • Interleukin-2 (IL-2)
    • Secreted primarily by Helper T-cells
      • mainly by Th1 cells to amplify its own response
    • Stimulates growth of all lymphocytes
      • T-cells (CD8+ and CD4+)
        • First cytokine produced by T-cells after activation
        • Helps to amplify adaptive immune response
      • NK cells
        • Anti-tumor effects via NK cell stimulation is rationale behind use of IL-2 analogues in cancer (e.g. aldesleukin)
      • B cells
    • Production dependent on calcineurin