Description: This antibody reacts on a 49kDa protein designated as CD1a. CD1a is a non-polymorphic MHC Class 1 related cell surface glycoprotein, expressed in association with Beta 2 microglobulin. CD1a is expressed by cortical thymocytes, epidermal Langerhan's cells, dendritic cells, interdigitating cells, on certain T-cell leukemias, and in various other tissues. CD1a is also expressed by some malignancies of T cell lineage and in histiocytosis X.