Immunomodulators

Immunomodulators are substances or drugs that modify the immune response. They can enhance (immunostimulants) or suppress (immunosuppressants) immune activity, and may act locally or systemically. They encompass small molecules, biologic agents, vaccines, and adjuvants used to influence innate and adaptive immunity.

Immunomodulation can occur through diverse mechanisms. Agents may inhibit cytokine signaling or T cell activation, alter antigen presentation, deplete specific immune cell populations, or affect immune cell trafficking. Some therapies aim to unleash immune responses against cancer or infections, while others dampen excessive or misdirected immunity to treat autoimmune or inflammatory diseases. Vaccines and vaccine adjuvants modulate the magnitude and quality of immune responses to specific antigens.

Classes and representative agents encompass a range of indications. Immunostimulants include interferons, interleukins, and immunomodulatory drugs such as thalidomide and its analogs. Biologic immunomodulators include cytokine inhibitors (for example, TNF inhibitors, IL-6 inhibitors), B cell–targeting antibodies (rituximab), and T cell–co-stimulation modulators (abatacept). Immunosuppressants cover corticosteroids, calcineurin inhibitors (cyclosporine, tacrolimus), and mTOR inhibitors (sirolimus). Cancer immunotherapy features checkpoint inhibitors (pembrolizumab, nivolumab) and cellular therapies. Vaccines and adjuvants represent preventive and modulatory aspects of the immune response.

Applications span autoimmune and inflammatory diseases, organ transplantation, cancer treatment, and adjunctive roles in infectious diseases. Safety considerations include risks of infection, immune-related adverse events, cytopenias, and organ toxicity, necessitating careful monitoring and individualized risk–benefit assessment.