The CD4 antigen is involved in the recognition of the type II MHC antigen. It is also a receptor for HIV. It is present on most T helper cells and normal thymocytes. The cytoplasmic portion of CD4 is associated with p56lck tyrosine kinase. CD4 expression is commonly found in human lymph nodes and tonsils. CD26 [also known as dipeptidyl peptidase IV (DPP IV), adenosine deaminase (ADA) binding protein]. 1 - 3 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. Cross-linking of CD26 using this antibody dramatically enhances the anti CD3-induced IL - 2 production.
ADABP; ADCP-2; Adenosine deaminase complexing protein 2; CD26; CD4; CD4 antigen (p55); CD4 antigen p55; CD4 receptor; Dipeptidyl peptidase 4; Dipeptidyl peptidase 4 membrane form; Dipeptidyl peptidase 4 soluble form; Dipeptidyl peptidase IV; Dipeptidyl peptidase IV membrane form; Dipeptidyl peptidase IV soluble form; dipeptidyl-peptidase 4; dipeptidylpeptidase 4; dipeptidylpeptidase IV (CD26, adenosine deaminase complexing protein 2); DPP IV; DPP-IV; T-cell activation antigen CD26; T-cell surface antigen T4/Leu-3; T-cell surface glycoprotein CD4; TP103