Difference Between Alloantibody and Autoantibody

The key difference between alloantibody and autoantibody is that the alloantibody is an antibody produced against alloantigens, which are foreign antigens introduced by transfusion or pregnancy. Meanwhile, the autoantibody is an antibody that reacts with self-antigens.

Antibodies are produced as a result of an immune response. They may reflect the presence, nature and intensity of an immune response. The immune system should be able to identify self-antigens and foreign antigens separately. It is critical for its function.  B cells of the immune system produce antibodies against antigens. Alloantibodies and autoantibodies are two types of such antibodies. Alloantibodies are produced due to the introduction of alloantigens into the body by transfusion or pregnancy. In contrast, autoantibodies are antibodies that react with self-antigens. The reaction of autoantibodies with self-antigens is responsible for inflammation, damage and dysfunction of tissues and organs, leading to signs and symptoms of autoimmune disorders.

CONTENTS

1. Overview and Key Difference
2. What is Alloantibody 
3. What is Autoantibody
4. Similarities Between Alloantibody and Autoantibody
5. Side by Side Comparison – Alloantibody vs Autoantibody in Tabular Form
6. Summary

What is an Alloantibody?

Alloantibody is an antibody produced against alloantigens that enter into the body by transfusion or pregnancy. Alloantigens are not the constituents of the organism itself. They are produced in the circulation. Moreover, alloantigens differ in individuals of the same species by amino acid sequences.

Alloantigens are proteins or other substances, such as histocompatibility or red blood cell antigens present in the members of the same species. These alloantigens are capable of inducing the production of alloantibodies in the other members of the same species. Certain alloantibodies cause harm to patients by destructing the transfused red blood cells or harming the fetus when the mother carries an alloantibody against an antigen on the baby’s red blood cells.

What is an Autoantibody?

An autoantibody is an antibody that works against a person’s own body antigens. In other words, autoantibodies are the antibodies that attack self-antigens. Therefore, they are harmful antibodies that cannot differentiate self and non-self antigens. These antibodies mistakenly target and react with a person’s own tissues or organs. Hence, these autoantibodies are responsible for many autoimmune diseases. They are useful as biomarkers of diseases. Autoantibodies are frequently found in healthy individuals.

Normally our immune system self-regulatory processes neutralize and eliminate autoantibodies before their maturation. But when it fails to neutralize, these autoantibodies damage cells, tissues and organs. Autoantibodies destroy our cells by phagocytosis or cell lysis. Antinuclear antibodies, antineutrophil cytoplasmic antibodies, anti-double-stranded DNA, anticentromere antibodies, anti-histone antibodies, and rheumatoid factor are several types of autoantibodies.

What are the Similarities Between Alloantibody and Autoantibody?

• Alloantibody and autoantibody are two types of antibodies producing as a response to immune reactions.
• They are mainly proteins.
• Moreover, they bind with their specific antigens.

What is the Difference Between Alloantibody and Autoantibody?

Alloantibodies are the antibodies that work against alloantigens introduced to the body by transfusion or pregnancy. In contrast, autoantibodies are the antibodies that react with the components of the body’s own tissues and organs. So, this is the key difference between alloantibody and autoantibody.

Moreover, another difference between alloantibody and autoantibody is that the alloantibodies bind with alloantigens and destroy them. But, the autoantibodies bind with self-antigens and damage a person’s own body tissues and organs.

Summary – Alloantibody vs Autoantibody

Alloantibody and autoantibody are two types of antibodies generated in our body against antigens. Alloantibody is produced against alloantigens, which are foreign antigens introduced into our body by transfusion or pregnancy, while autoantibody is an antibody that reacts with self-antigens. Thus, this is the key difference between alloantibody and autoantibody. Autoantibodies cannot discriminate self-antigens and nonself antigens while alloantibodies can recognize alloantigens and only bind with alloantigens which are foreign antigens present in the other members of the same species.

Reference:

1. “Autoantibodies.” Lab Tests Online, Available here.
2. “Isoantibodies.” Wikipedia, Wikimedia Foundation, 30 Jan. 2019, Available here.

Image Courtesy:

1. “Antibody illustration” By DigitalShuttermonkey – Recreated jpg originally uploaded by Muntasir Alam (CC BY-SA 3.0) via Commons Wikimedia