Therapeutic antibodies

Monoclonal antibody therapy is a form of immunotherapy that uses monoclonal antibodies (mAb) to bind monospecifically to certain cells or proteins. This may then stimulate the patient's immune system to attack those cells. Alternatively, in radioimmunotherapy a radioactive dose localizes on a target cell line, delivering lethal chemical doses. More recently antibodies have been used to bind to molecules involved in T-cell regulation to remove inhibitory pathways that block T-cell responses, known as immune checkpoint therapy.

It is possible to create a mAb specific to almost any extracellular/ cell surface target. Research and development is underway to create antibodies for diseases (such as rheumatoid arthritis, multiple sclerosis, Alzheimer's disease, Ebola and different types of cancers).

Immunoglobulin G (IgG) antibodies are large heterodimeric molecules, approximately 150 kDa and are composed of two kinds of polypeptide chain, called the heavy (~50kDa) and the light chain (~25kDa). The two types of light chains are kappa (κ) and lambda (λ). By cleavage with enzyme papain, the Fab (fragment-antigen binding) part can be separated from the Fc (fragment constant) part of the molecule. The Fab fragments contain the variable domains, which consist of three antibody hypervariable amino acid domains responsible for the antibody specificity embedded into constant regions. The four known IgG subclasses are involved in antibody-dependent cellular cytotoxicity.

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