Monoclonal antibodies (mAb)

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at NSU

Monoclonal antibodies are produced by hybridomas. A hybridoma is a product of cell fusion between:

- normal antibody producing B cell (plasma cell)
- myeloma cell

Typically, spleen cells from an immunized mouse are fused with myeloma cells by using polyethylene glycol (PEG) to produce a hybrid cell line called a hybridoma.

Each hybridoma is descended from a single cell and all the antibodies produced by that cell are identical. These antibodies are called monoclonal antibodies (mAbs).

Monoclonal antibodies (mAbs) nomenclature related to sufix

-omab - murine, only of mouse origin. Murine component is 100%

-ximab - chimeric human/mouse. mAb combines murine mAb variable regions with the constant region of human antibody. Murine component is 30%

-zumab - humanized. mAb combines murine mAb variable regions with a portion of a human IgG molecule. Murine component is less than 10%

-umab - "fully" human mAb cloned into a bacteriophage

-cept - fusion of a receptor to the Fc part of human IgG1

Examples of monoclonal antibodies (mAb) in clinical practice

- Rituximab - against CD20. Used in autoimmune diseases, B cell lymphomas
- Anti-CD20 monoclonal antibody ocrelizumab helps patients with relapsing-remitting multiple sclerosis (MS) (Lancet, 2011).
- Omalizumab - againts FcεRI (cε3). Used in asthma
- Adalimumab - against TNF-α. Used in rheumatoid arthritis
- Palivizumab - against RSV. Used to prevent RSV infection in infants with bronchopulmonary dysplasia
- Mepolizumab - against IL-5. Used in hypereosinophilic syndrome and patients with eosinophilic asthma
- Daclizumab - against IL-2 receptor α chain (CD25). Used to prevent renal allograft rejection
- Natalizumab - against α 4 chain of integrin molecule. Used in multiple sclerosis (MS)
- Abciximab - against integrin αIIβ3. Used in acute coronary syndromes (ACS)
- Anti-IL-17 Receptor Antibody Brodalumab Helps Patients with Psoriasis - NEJM, 2012.
- Anti–Interleukin-17 Monoclonal Antibody Ixekizumab Improves Chronic Plaque Psoriasis - NEJM, 2012.
- Natalizumab-Associated Progressive Multifocal Leukoencephalopathy (PML) - NEJM lists the risk factors
- In 2014, FDA Approved New Drug for Crohn Disease and UC: vedolizumab (Entyvio), an injectable monoclonal antibody. Vedolizumab, an integrin receptor antagonist http://buff.ly/1lFuRtv

References

Online Book of Biologic Therapies (monoclonal antibodies, etc.) by the Clinical Immunology Society

Related reading

Allergy to monoclonal antibodies: cutting-edge desensitization methods - Expert Reviews, 2012.

mAb: If it ends in -mumab, it's a fully human protein, -zumab is humanized (10% mouse), -ximab is chimeric (33% mouse). ACP blog, 2012.

Published: 08/12/2008
Updated: 05/25/2012