Recognizes a glycoprotein of 110kDa, identified as CD26. It is an atypical serine protease belonging to the prolyl oligopeptidase family. It is expressed on lymphocyte cells and is upregulated during T-cell activation. CD26 is also expressed on activated B cells and natural killer cells and abundantly on epithelia. CD26 is implicated in a variety of biological functions including T-cell activation, cell adhesion with extracellular matrix such as fibronectin or collagens, and in HIV infection.