The term “Isotype switching” in its own sense does not look much like the medical meaning it actually portrays. Isotype Switching, simply, is a concept that refers to the switching of isotypes. But then, what are isotypes? Just in case you are familiar with biology or medicine, isotypes are molecules on antibody cells that refer to the genetic variations or differences in the constant region of the heavy chain of the immunoglobulins classes and sub-classes. It’s already getting boring, isn’t it? That is not my aim anyway. I only needed to clarify the terminology so you can learn something new or better understand the concept at least. More importantly, I want to show you an important lesson you can learn from the concept of isotype switching to improve your daily life. But I have decided to spice it up with a little story with the hopes that you will better understand the direction I am driving to.
Once upon a time, there was an old woman who buys salt in very large lumpy form. As a trader on salt, she just could not wait for the local manufacturers to disassemble the salt rocks before she buys them. So she had to grind them in powdery salt by herself. The only advantage she had doing this was that she would make more profit because she realized more pints and bags of salt from seemingly fewer lumps of salt. The big lumps were actually underestimated, you will agree with me. But we can accept the fact that she is also making the salt useful by processing them into the powdery form since no one would actually want to use the lumps for cooking or whatever.
Isotype Switching – The Concept
In the body, there are there broad types of blood cells; the red blood cells, the white blood cells, and the platelets. Isotype switching, however, applies to the behaviour of some of the white blood cells referred to as the B lymphocytes/B cells. B cells are the subset of lymphocytes that produce the antibodies or immunoglobulin. Antibodies exert their primary effects by binding to antigens, which are produced by other body cells and foreign cells/particles. The resultant outcome is the destruction of the cell that possesses the foreign antigen.
Antibodies produced by each activated B cell (an activated B cell is called a plasma cell) must be specific to the organism or antigen that triggered it. That means antibodies produced against antigen X can only attack and bind to X and destroy every cell possessing X. B cells have receptors made of Immunoglobulins D and M (immunoglobulins D and M form part of the B cell receptor. These remain confined to the B cells and are not released against invading antigenic cells or substances. However, they serve as the templates from which other Immunoglobulins will be produced on activation. Now you would want to ask, how can only M and D be used to produce the other different antibody molecules (IgG, IgA, IgD, IgE, and IgM)? It is by employing a mechanism termed Isotype Switching.
Isotype switching is a mechanism by which an activated B cell (plasma cell) is able to change its effector antibody production to forms that are different from the Immunoglobulin D(IgD) and Immunoglobulin M(IgM) originally resident on the membranes of B cells. They, therefore, produce other kinds of immunoglobulins G, A and/or E depending on the body’s need and situation of the foreign antigen. [The five antibody types are IgG, IgA, IgD, IgE, and IgM]. Check here to read more about the antibodies.
What Is The Mechanism of The Switch
Recall my story of the salt seller at the beginning of this post. When antigens are presented to B cells, they become activated to produce antibodies to counteract the antigen and the organism or particle bearing that antigen.
This they do by changing the molecular structure of their tail portion. I didn’t mention tail earlier but that is an important part of the immunoglobulin structure. The tail portion, also known as the Fc (constant chain) portion, is the part that produces the IgG, IgA and IgE antibodies after which the antibodies are secreted into the other potential areas of entry of microorganisms/foreign antigenic particles including the skin and mucous membranes. This way, their effectiveness in fighting off the antigen or warding it from successful re-entry is greatly amplified. Different antibodies are stationed to different parts of the host body such that those that are functional in the mouth may not also be functional or stable in the human bloodstream. Therefore, Isotype switching ensures that protection is conferred at almost every areas of the body. Does this not remind you of the salt trader?
The Socioeconomic Import of Isotype Switching
Just like the old woman, they convert what they already have to more useable forms. In reality, you naturally have resources within or around you that may not be so useful in their raw forms. But you might be shocked to realize that some of these raw materials can be refined to unbelievably useable forms. Discovering usefulness in things that would otherwise look useless is a form of identifying opportunities. And some people have dared to make fortunes from some of these kinds of ventures. This was how businesses were formed, this was how inventions were made. Understanding this concept of isotype switching will ultimately enable you to make very productive switches that will make you more useful and productive. As a matter of fact, what you already has becomes a potential raw material either for profit or for pleasure. It’s not too late to have fun like the B cells and I can tell you that they feel happy about their productivity too.
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