Monoclonal Antibodies

Monoclonal antibodies are identical and specific antibodies made by identical immune cells. They are grown in culture and therefore are clones of the unique parent cell. The technology required to produce monoclonal antibodies is extensive and the time it takes from the start of the process to the finished and pure monoclonal antibody is longer than that of a polyclonal antibody. The process is very detailed but grossly simplified involves the immunization of a mouse with an immunizing antigen. The spleen cells of the mouse are used in combination with rapid growing cells in culture to produce hybridomas. These hybrid cells are grown in-vitro or in-vivo and selected for specificity. At Abcore, 6-8 weeks is allotted for in vivo monoclonal antibody production via mouse ascites. Purification is also available. Once hybridomas are manufactured, the process is easily duplicated and the antibodies come from a renewable source where all lots are identical. The many advantages of monoclonal antibodies stem from their ability to bind to one specific site on one antigen rather than a mixture of antibodies that can bind to multiple sites on an antigen like polyclonal antibodies. These advantages include homogeneity and specificity. The immunizing antigen does not need to be pure in order to produce large amounts of the specified monoclonal antibody and the selection process allows for multiple specific monoclonal antibodies be produced from a single immunizing antigen. However, they can produce cross reactions and still bind to unrelated antigens despite their specificity to the particular portion of the immunizing peptide. Their affinity can be lower than that of polyclonal antibodies, and their specificity is so high that they are not tolerable to minor conformational changes on the native proteins.

Anti-CD73 antibody is the antibody to CD73 target. This is a mouse monoclonal antibody (clone AD2) which recognizes ecto-5’-nucleotidase. This is a glycoprotein anchored to the extracellular leaflet of the plasma membrane by GPI. The target is an enzyme that catalyzes the dephosphorylation of AMP to adenosine. CD73 is expressed in all different types of cells like epithelial, muscle, endothelial, neutrophils, lymphocytes, and fibroblasts. Inflammatory mediators support the expression of CD73 and its activity which eventually leads to the release of adenosine. Adenosine serves an important function in that it modulates inflammation through adenosine receptors. CD73 is expressed in a number of blood cancers including lymphoma and leukemia. Individuals who are immunodeficient usually express low levels of the CD73 protein. The Anti-HLA-DR antibody is a mouse monoclonal antibody (clone L243) that recognizes specifically HLA-DR molecules that are either loaded with a peptide or empty. HLA-DR is an MHC class II glycopreotein that binds to peptides that have been intracellularly processed. HLA-DR then presents those processed peptides to Th cells anchored into the plasma membrane. Together with other MHC II molecules HLA-DR plays a very important role in the immune system. It is expressed on antigen presenting cells like dentritic cells, B lymphocytes, monocytes, and macrophages.