Immunomodulators - Definition, Classifications, Mechanism - imdip

Definition of Immunomodulators:

Immunomodulators are medicinal substances that enhance or suppress the body's immune response.

Types of Immunomodulators:

Immunostimulants:

Immunostimulants help to increase the immune system’s activity. They are used to treat immune deficiencies, chronic infections, and cancer.

Example of Immunostimulants:

• Levamisole- Restores T-cell function
• Thymosin- Enhances T-lymphocyte function
• BCG vaccine- Used in bladder cancer as an immune stimulant
• Interferons (IFN-α, IFN-β)- Antiviral and antitumor activity
• Interleukins (e.g., IL-2)- Stimulates T-cell proliferation

Immunosuppressants:

Immunosuppressants help to reduce or stop the immune system’s activity. They are used in organ transplantation, autoimmune diseases, and hypersensitivity disorders.

Example of Immunosuppressants:

• Glucocorticoids- Prednisone, Dexamethasone
• Calcineurin inhibitors- Cyclosporine, Tacrolimus
• mTOR inhibitors- Sirolimus, Everolimus
• Cytotoxic drugs- Azathioprine, Methotrexate, Cyclophosphamide
• Biologics- Monoclonal antibodies like Rituximab, Infliximab

Classification of Immunosuppressants:

Immunosuppressive drugs are used to suppress the immune response, particularly in autoimmune diseases, organ transplantation, and inflammatory conditions.

Let's discuss the classification of Immunosuppressive Agents:

Calcineurin Inhibitors

Mechanism: Inhibit T-cell activation by blocking calcineurin, a protein phosphatase.
Examples: Cyclosporine, Tacrolimus

mTOR Inhibitors

Mechanism: Inhibits T-cell proliferation by blocking the Mammalian Target of Rapamycin Inhibitors (mTOR) pathway.

Examples: Sirolimus (Rapamycin), Everolimus

Antiproliferative Agents / Antimetabolites

Mechanism: It inhibits DNA synthesis, thereby suppressing immune cell proliferation.
Examples: Azathioprine, Mycophenolate mofetil (MMF), Methotrexate (also used in autoimmune diseases)

Biologics / Monoclonal Antibodies

Mechanism: It targets specific immune cells or cytokines.
Examples: Anti-TNF agents (e.g., infliximab, adalimumab), IL-2 receptor antagonists (e.g., basiliximab, daclizumab), Rituximab (anti-CD20), Alemtuzumab(anti-CD52)

Corticosteroids

Mechanism: Broad anti-inflammatory and immunosuppressive effects by inhibiting multiple cytokines.
Examples: Prednisone, Methylprednisolone, Dexamethasone

T-Cell Depleting Agents

Mechanism: It depletes or inhibits T-lymphocytes.
Examples: Antithymocyte globulin(ATG), Muromonab-CD3(OKT3)

Janus Kinase (JAK) Inhibitors

Mechanism: It inhibits the JAK-STAT signaling pathway involved in cytokine transmission.

Examples: Tofacitinib, Baricitinib