Zenepax binds with high-affinity to the Tac subunit of the high-affinity IL-2 receptor complex and inhibits IL-2 binding. The IL-2 receptor (Tac) subunit is expressed on activated but not resting lymphocytes.
Zenapax functions as an IL-2 receptor antagonist. Specifically it inhibits IL-2-mediated activation of lymphocytes, a critical pathway in the cellular immune response involved in allograft rejection.
Most likely removed by opsonization via the reticuloendothelial system when bound to lymphocytes.