Bleselumab is a monoclonal antibody primarily used in clinical research and therapeutic development for immune-mediated diseases. It targets CD40, a co-stimulatory protein found on antigen-presenting cells, blocking the CD40-CD154 interaction that plays a critical role in T-cell activation and immune response regulation.

This antibody has been investigated in transplant medicine to prevent organ rejection, particularly in kidney transplantation, due to its ability to suppress T-cell-dependent immune activation without broad immunosuppression. By inhibiting the CD40 signaling pathway, bleselumab reduces the risk of acute rejection and may allow for reduced reliance on calcineurin inhibitors, which have significant long-term toxicity.

It has also been explored in autoimmune conditions where dysregulated immune activation is a key component, such as lupus nephritis and rheumatoid arthritis. Its mechanism offers a targeted approach to modulate the immune system while preserving general immune function.

Due to its specificity, bleselumab serves as a reference tool in immunoassays and flow cytometry for studying CD40 expression and function in human immune cells.