The CD38 (HIT2) antibody recognizes a 45-kDa single chain type-II transmembrane glycoprotein e, Xenopus/Amphibian,pressed on thymocytes, activated T and B cells, hematopoietic progenitors and terminally differentiated B cells/plasma cells (at high levels). CD38 antigen is also present on monocytes, dendritic cells, NK cells and some epithelial cells. CD38 is a NAD glycohydrolase and is a regulator of cell activation and proliferation, and also involved in adhesion between human lymphocytes and endothelial cells.