Muromonab-CD3

Muromonab-CD3 (generic name) is a monoclonal antibody (mAb), also known as Orthoclone OKT3 (Brand name). It is a mouse-derived (murine) monoclonal antibody that specifically binds to the CD3 (T3) protein found on the surface of T cells.

Of historical note is that this was the first mAb approved for clinical use in humans.

It is an intravenous drug, used for the prevention and treatment of transplant rejection.