Immunosuppressive agents

Immunosuppressive agents

Immunosuppressive agents

  • Immunosuppressive agents are those that suppress immune response.
  • They are used in transplantation surgery and in situations that require suppression of host immunity.

The agents are as follows:

  1. X-irradiation
  2. Radiometric drugs
  3. Corticosteroids
  4. Antimetabolites
  5. Antilymphocyte serum


  • Sublethal dose of irradiation is toxic to replicating cells and is used to suppress antibody formation.
  • Antibody production ceases after 24 hours of receiving irradiation.

Radiometric drugs:

  • These include alkylating agents (such as cyclophosphamide, nitrogen mustard, etc.), which suppress antibody production.
  • Cyclophosphamide, given for 3 days, completely suppresses the antibody response.
  • It selectively prevents replication of B cells.


  • Corticosteroids are anti-inflammatory drugs that diminish the responsiveness of both B and T cells.
  • They alter maturation of activated cells by suppressing the production of interleukins.
  • They suppress delayed hypersensitivity, but in therapeutic doses for a short period, they have little effect on the production of antibodies.


  • These include folic acid antagonists (such as methotrexate); analogs of purine (6-mercaptopurine and azathioprine); and analogs of cytosine (cytosine arabinose); and uracil (5-fluorouracil).
  • These substances inhibit DNA and RNA synthesis, thereby inhibiting the cell division and differentiation, which is essential for cellular and humoral immune responses.
  • These are usually used for prevention of graft rejection.

Antilymphocyte serum:

  • Antilymphocyte serum (ALS) is a heterogeneous antiserum raised against T lymphocytes.
  • The ALS acts mainly against circulating lymphocytes but not against lymphocytes in lymphoid organs.
  • It is mainly used to prevent graft rejection in transplantation surgery.

Immunosuppressive agents


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