The main difference between autoantibodies and alloantibodies is that autoantibodies react with self-antigens, whereas alloantibodies are produced against alloantigens.
Antibodies are produced within a body as a result of an immune response. They protect the body against unwanted foreign substances that enter your body. These antibodies bind to unwanted substances and eliminate foreign substances. These foreign substances may be bacteria, venom, allergens, fungi, viruses, and other toxins. B cells produce antibodies. They are specialized white blood cells. When antigens encounter B cells, they divide and produce clones of B cells or plasma cells. These plasma cells then release antibodies into the lymphatic system and blood. Antibodies are present in various parts of the body. We can categorize antibodies into two types: autoantibodies and alloantibodies.
Key Areas Covered
1. What are Autoantibodies
– Definition, Production, Features
2. What are Alloantibodies
– Definition, Production, Features
3. Difference Between Autoantibodies and Alloantibodies
– Comparison of Key Differences
Key Terms
Autoantibodies, Alloantibodies, Antibodies
What are Autoantibodies
Autoantibodies are antibodies an organism produces in response to a constituent of its own tissues. When a person has got an autoimmune disorder, the body produces one or more autoantibodies. This happens when the system is incapable of distinguishing between self and non-self-antigens. These self-antigens may be proteins, carbohydrates, nucleic acids, or fat. These types of antigens can be found in all cell types, but sometimes they may be present in certain specific tissues, as well. Information related to autoimmune disease could be obtained by the level of serum autoantibodies. Autoantibodies can be detected in patients with cancer or with severe tissue damage. Sometimes, autoantibodies are even present in healthy people. In a very small fraction of healthy people, the presence of these autoantibodies may cause the development of autoimmune diseases such as rheumatoid arthritis. In fact, autoantibodies can cause about 2.5% of autoimmune diseases.
Immunoblotting, enzyme-linked immunosorbent assay, chemiluminescence immunoassay, radioimmunoassay, and indirect immunofluorescence assay are the methods that help to detect autoantibody levels.
Natural autoantibodies provide the first line of defense. This is because of the high reactivity observed against the microbial agents. They also prevent inflammation by removing oxidized lipids, proteins, and dead cells. Natural autoantibodies maintain immune system homeostasis. This happens by binding self-antigens non-specifically and with low affinity when natural autoantibodies can prevent highly autoreactive clones from reacting strongly with self-antigen.
What are Alloantibodies
Alloantibodies are the circulating antibodies that are a result of previous antigenic stimulation from previous transfusion of blood products, pregnancy, or some other event. Examples of such alloantibodies are anti-K and anti-E. Alloantigens are not constituents of the organism itself. They are proteins of other substances, such as histocompatibility or red blood cell antigens, which are present in the same species’ membranes.
The formation of alloantibodies is alloimmunization. These antibodies commonly form against antigens from blood groups such as Rh(which includes common antigens D, C, and E). Only some alloantibodies cause clinical harm to patients. Such antibodies are clinically significant. This is because they lead to the destruction of transfused red blood cells or because they may harm a fetus or a newborn when the mother carries an alloantibody that is against the antigens on the baby’s red cells.
Moreover, the ability to develop red blood cells is only possible with a specific group of blood recipients, namely immune responders. Additionally, the inflammation and genetic background in these immune responders favor antigen-presenting events and strengthen the Th2 response.
Difference Between Autoantibodies and Alloantibodies
Definition
Autoantibodies are antibodies an organism produces in response to a constituent of its own tissues. On the other hand, alloantibodies are the circulating antibodies that are a result of previous antigenic stimulation from previous transfusion of blood products, pregnancy, or some other event.
Production
Moreover, autoantibodies react with self-antigens, while alloantibodies are produced against alloantigens.
Function Against
Autoantibodies function against self-antigens, whereas alloantibodies function against foreign antigens.
Antigens
Antigens of autoantibodies are self-antigens, whereas antigens of alloantibodies are alloantigens.
Conclusion
The body produces antibodies as a result of an immune response. They protect the body against foreign substances that enter the body. The main difference between autoantibodies and alloantibodies is that autoantibodies react with self-antigens, whereas alloantibodies form against alloantigens.
Reference:
1. “What are autoantibodies?” Testing.
Image Courtesy:
1. “Antibody IgG1 structure” By Tokenzero – Own work (CC BY-SA 4.0) via Commons Wikimedia
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