Definition

A synthetic radioimmunoconjugate comprised of a humanized anti-interleukin-2 (IL-2) antibody linked to the radioisotope Yttrium 90 with potential antineoplastic activity. Daclizumab binds with high affinity to the Tac (also called CD25) subunit of the IL-2 receptor complex and inhibits the binding of IL-2, thereby blocking the IL-2-mediated activation of lymphocytes. As Yttrium Y 90 daclizumab, daclizumab delivers radiation specifically to lymphocytes that express the IL-2 receptor.