Basiliximab is?
**Core Concept**
Basiliximab is a monoclonal antibody targeting the interleukin-2 (IL-2) receptor alpha subunit (CD25), which plays a crucial role in the activation and proliferation of T lymphocytes. By binding to CD25, basiliximab prevents the interaction between IL-2 and its receptor, thereby inhibiting T-cell activation and proliferation.
**Why the Correct Answer is Right**
Basiliximab is used as an immunosuppressive agent to prevent acute rejection in organ transplantation, particularly in kidney and liver transplants. This is achieved by reducing the activity of T lymphocytes, which are central to the immune response against the transplanted organ. The mechanism of action involves the binding of basiliximab to CD25 on the surface of activated T cells, thereby blocking the IL-2 receptor and preventing the subsequent activation and proliferation of these cells.
**Why Each Wrong Option is Incorrect**
**Option A:** Basiliximab is a calcineurin inhibitor. **Incorrect** because basiliximab is a monoclonal antibody targeting IL-2 receptor alpha subunit, not a calcineurin inhibitor like tacrolimus or cyclosporine.
**Option B:** Basiliximab is used to treat autoimmune diseases. **Incorrect** because while basiliximab does modulate the immune response, its primary use is in preventing acute rejection in organ transplantation, not treating autoimmune diseases.
**Option C:** Basiliximab is a corticosteroid. **Incorrect** because basiliximab is a monoclonal antibody, not a corticosteroid like prednisolone or dexamethasone.
**Clinical Pearl / High-Yield Fact**
Basiliximab is typically administered in combination with other immunosuppressive agents, such as calcineurin inhibitors and corticosteroids, to achieve optimal immunosuppression and prevent acute rejection in organ transplantation.
**Correct Answer:** C. Basiliximab is a monoclonal antibody targeting the interleukin-2 (IL-2) receptor alpha subunit (CD25), used to prevent acute rejection in organ transplantation.