Definition

A radioimmunoconjugate composed of basiliximab, a chimeric, mouse-human monoclonal antibody directed against the alpha subunit of interleukin-2 receptor (IL-2R alpha, CD25 or Tac antigen), and conjugated with the bifunctional, macrocyclic chelating agent tetra-azacyclododecanetetra-acetic acid (DOTA) and labeled with the radioisotope indium In 111, with potential use as an imaging agent. Upon administration of indium In 111-DOTA- basiliximab, the basiliximab moiety targets and binds to IL-2R alpha expressed on the surface of activated T lymphocytes. Upon binding and gamma scintigraphy, IL-2R alpha-expressing T cells can be visualized and the binding and biodistribution of basiliximab can be assessed.