The P67.6 monoclonal antibody reacts with human CD33 (also known as GP67 and P67),
a 67 kDa type I transmembrane glycoprotein that is a member of the
Siglec (sialic acid-binding Ig superfamily lectin) family. It is highly specific
to the hematopoietic compartment and is expressed on monocytes, activated T cells,
granulocytes, myeloid progenitors, and mast cells.