Antimetabolites, cyclosporine and antibody preparations for immunosuppression
THE CONTEXT
These agents inhibit immune responses through interference with nucleic acid synthesis, selective inhibition of helper T cells, or antibody preparations directed against lymphocytes.
Antimetabolites
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Antimetabolites interfere with DNA synthesis, RNA synthesis or both, inhibiting the cell division and differentiation needed for humoral and cellular immune responses.
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The listed agents include methotrexate as a folic acid antagonist and cyclophosphamide as an alkylating agent.
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The listed nucleotide analogues include the purine analogues 6-mercaptopurine and azathioprine, the cytosine analogue cytosine arabinoside, and the uracil analogue 5-fluorouracil.
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Many antimetabolites are used clinically to prevent graft rejection.
Cyclosporine
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Cyclosporine is a cyclic polypeptide derived from the soil fungus Tolypocladium inflatum.
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It selectively inhibits helper T-cell activity without being cytotoxic to lymphocytes or having antimitotic activity.
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Rapamycin is identified as a related drug.
Antibody preparations
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Anti-lymphocyte serum (ALS)* is a heterologous antiserum against lymphocytes.
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The antibody preparation against thymus cells is called anti-thymocyte serum (ATS).
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The corresponding globulin preparations are termed ALG and ATG, respectively; these preparations were used to prevent graft rejection.