Von FITBOOK | Feb 18, 2023 at 5:02 p.m
They fight for our health when it is threatened: Antibodies are the immune system’s silver bullet. How they are formed, how they work.
Most of us have probably already heard that antibodies play a crucial role in fighting pathogens in our body. FITBOOK gives a brief overview of the formation and function of immunoglobulins.
What are antibodies?
Antibodies, also known as immunoglobulins (Ig for short), are special proteins. As part of the immune system, they fight pathogens. There are five different classes of antibodies in humans, which differ in their occurrence and functions: IgM, IgD, IgG, IgE and IgA. Igs.
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How are antibodies produced?
They form a subgroup of white blood cells. These B lymphocytes are distributed from the bone marrow primarily to the lymph nodes and the spleen. Antibodies are already prepared to fight pathogens before they circulate in the body: the B cells have several thousand receptors on their surface, all of which recognize a very specific antigen. Each B cell recognizes a different antigen – but only one. In this capacity, they constantly check the body for antigens.
What are the functions of antibodies?
They bind to substances that the immune system has identified as “foreign” and wants to fight (called antigens). To start the fight, the Y-shaped antibodies bind to antigens that have been recognized as foreign and are now to be fought. The scavenger cells recognize the signal and eliminate the antigens. If the whole thing happens with bacteria or viruses, it may be that the pathogens are already rendered harmless by the binding of the antibodies – and a virus, for example, cannot even cause any damage in a body cell.
Antibodies work like a kind of memory: they are able to store characteristics of a pathogen (e.g. following an infection). In this way, it can be combated even more quickly and efficiently following a second infection.
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How can an antibody detection be carried out?
There are tests to check if there are antibodies, viruses (and other foreign particles such as toxins and hormones) in the body, and if the immune system has started making antibodies. The so-called “enzyme-linked immunosorbent assay” (short: ELISA) is an example of this: The patient submits a blood or urine sample. Now the structure of antibodies and antigens (as mentioned above, antibodies have the property of binding to antigens) are made visible in color with the help of enzymes and dyes.
What if typical antibodies are missing?
Abnormal levels of antibodies in the blood can impair wound healing, increase the risk of bacterial infections and result in recurrent, even life-threatening infections. A distinction must be made between primary and secondary antibody deficiency.
In the case of congenital immune defects (primary antibody deficiency), the susceptibility to infection is often already increased in childhood – but they can also go unnoticed for a long time and then suddenly show up. These patients then have to take immunoglobulin preparations for life. Tumor or autoimmune diseases (such as type 1 diabetes mellitus) can lead to an antibody deficiency: This is referred to as an acquired or secondary antibody deficiency.