Since 1986, when muromonab-CD3 was approved for the prevention of organ transplant rejection, monoclonal antibodies are being increasingly used. Nowadays there are a lot of these medicines approved, in Europe and United States, for the tretament of complex diseases such as rheumatoid arthritis, multiple sclerosis or cancer, and monoclonal antibodies biosimilars of some of them are available. We have heard of them, but do we really know what they are?
1. Our immune system
The human immune system is an extraordinarily complex network of cells, tissues and organs, which work together to defend the body from the attacks of foreign agents (bacteria, viruses, fungi or parasites)2.
The cells of the immune system, organised in groups and subgroups, comprise a dynamic and sophisticated communications network, patrolling the body and passing information between each other. When a foreign agentis detected, the cells undergo changes that allow them to fight against it. They also release chemical substances that are a signal to recruit more cells of the immune system, which move towards the site of the attack2.
The main characteristic of our immune system is its astonishing capacity to distinguish the cells of our own body from foreign ones. Our cells carry a marker that identify them as coming from our own immune system, which stops them being attacked by it. Foreign cells do not carry this marker, or they carry a different one, and they are thus recognised as foreign bodies and attacked by the immune system2. This explains why transplanted tissue is sometimes rejected by the recipient2. In general, any substance that could trigger an immune response is called an antigen2.
2. Parts of the immune system
The immune system is made up of a wide range of cells, which communicate with each other, come into direct contact, or release chemical messages called cytokines2.
Some are large white cells that are able to swallow and digest particles or foreign cells, generically called phagocytes2. However, the immune system is primarily made up of lymphocytes. These cells are further subdivided into two types: T lymphocytes, which target or regulate the immune response but which may also attack invading cells2; and B lymphocytes, whose function is to segregate the antibodies(large Y-shaped molecules, belonging to the immunoglobulin family)2. Each B lymphocyte produces a specific antibody against a specific antigen (e.g. the flu virus). When an antibody binds to its antigen, it is marked for destruction by T lymphocytes and phagocytes2.
To destroy bacteria, antibodies receive the help of a system of up to 25 proteins called the complement system, so called because it “complements” the antibodies2.
3. Monoclonal antibodies
Some antigens can be very complex, and every one of their parts can be recognised by different B lymphocytes, which will each produce antibodies against a different part of the antigen. These are polyclonal antibodies, as they come from several B lymphocyte clones3.
In 1975, as Khöler and Milstein were awarded the Nobel prize for developing a technique that made it possible to produce antibodies from a single B-lymphocyte clone, monoclonal antibodies were born3.These are able to recognise only one specific part of the antigen (called epitope), which makes them more specific to that antigen3and reduces the likelihood that they will attack other similar cells (cross-reactivity)3. This characteristic has been exploited to develop techniques that use monoclonal antibodies to mediate or modulate physiological effects in the body for therapeutic purposes, i.e.; their use in the treatment of diseases3.
The importance of monoclonal antibodies in clinical practice and their impact on healthcare budgets is growing, which is why mAbxience was founded in 2009 as an international biotechnology company specialising in the research, development and production of biosimilar monoclonal antibodies, and has been working ever since to improve access to these treatments4.
4. References
- European Medicines Agency – Find Medicine – European Public Assessment Reports. http://www.ema.europa.eu/ema/index.jsp?curl=pages%2Fmedicines%2Flanding%2Fepar_search.jsp&mid=WC0b01ac058001d124&searchTab=&alreadyLoaded=true&isNewQuery=true&status=Authorised&status=Withdrawn&status=Suspended&status=Refused&startLetter=View+all&keyword=. Accessed September 6, 2018.
- Kelly J. Understanding the Immune System How It Works. 2007:13–17. doi:10.1037/e609842007-001.
- Lipman NS, Jackson LR, Trudel LJ, Weis-Garcia F. Monoclonal Versus Polyclonal Antibodies: Distinguishing Characteristics, Applications, and Information Resources. ILAR J. 2005;46(3):258–268. doi:10.1093/ilar.46.3.258.
- La compañía biotecnológica de los medicamentos biosimilares. mABxience. https://www.mabxience.com/es/quienes-somos/. Accessed September 27, 2018.