Difference Between Complete and Incomplete Antibodies

Key Difference – Complete vs Incomplete Antibodies
 

Antibodies are composed of B cells and are immunoglobulins that take part in immune reactions. Antibodies can be of different classes depending on its structure, function, their type of reaction and the presence of accessory components. Antibodies are present in response to an antigen and thus, also termed as antigenic determinants. Once the antibody recognizes an antigen, it binds to the antigen specifically to form an antigen-antibody complex. The complex formation will eventually activate defense mechanisms or directly degrade the foreign body that enters the system. Agglutination is a type of antibody-antigen reaction that takes place as a host defense mechanism. During this reaction procedure, the antibody binds to the antigen and forms a complex which eventually clump together. Based on the property of agglutination, antibodies can be categorized into two main types; complete antibodies and incomplete antibodies.

Even though complete antibodies have the ability to agglutination with antigens after recognizing the antigen, incomplete antibodies do not have the ability to agglutination. Instead it only participates in recognizing and identifying the antigens. The key difference between the complete and incomplete antibodies is the ability or the inability of agglutination.

CONTENTS

1. Overview and Key Difference
2. What are Complete Antibodies
3. What are Incomplete Antibodies
4. Similarities Between Complete and Incomplete Antibodies
5. Side by Side Comparison – Complete vs Incomplete Antibodies in Tabular Form
6. Summary

What are Complete Antibodies?

Complete antibodies are a type of B cell immunoglobulins which take part in agglutination reactions after binding with an antigen. Complete antibodies have a specific property to bind to antigens and form clumps or agglutins, which enable to host phagocytes to identify the large foreign particle. Immunoglobulin G is a common type of a complete antibody. This will result in the activation of host defense mechanisms. This will engulf the complex as a whole. The two main applications of complete antibodies are hemagglutination and leukoagglutination. Antibodies produced by red blood cells and white blood cells are complete antibodies and hence participate in agglutination reactions. Therefore, these agglutination tests are done during blood transfusion procedures to check the compatibility of blood groups between the donor and the recipient. If the agglutination occurs, the blood groups are incompatible and vice versa. Complete antibodies are also produced against many bacterial infections, and these complete antibodies form agglutinations with bacterial pathogens and initiate phagocytic reactions.

Agglutination reactions are therefore used widely as diagnostic tests to identify the presence of a bacterial pathogen. Synthetic complete antibodies are tested in vitro for the suspect’s blood sample, and the presence of agglutins confer the occurrence of the particular infection. This test is of high precision and reliability.

What are Incomplete Antibodies?

Incomplete antibodies are mostly immunoglobulin M, and they do not participate in agglutination reactions upon binding to the antigen. Instead, these antibodies are produced in response to a particular antigen. The presence of incomplete antibodies can be detected in the serum as free antibodies by using antiglobulins. This test is referred to as the Coombs’ test.

In this test, the incomplete antibodies are allowed to bind to synthetic, specific target molecules known as antiglobulins. This is analyzed in order to determine the presence or the absence of the particular antibody in the serum. By doing this test procedure, a specific condition can be diagnosed and conformed. The incomplete antibodies are involved in indirectly activating an immune defense mechanism other than agglutination.

What are the Similarities Between Complete and Incomplete Antibodies?

• Both are composed of B cells.
• Both show high specificity.
• Both are involved in recognizing an antigen of a foreign cell.
• Both are used in in vitro diagnostic test procedures especially to determine the onset of infection.
• Samples such as serum or blood can be used for diagnostic tests of these antibodies.

What is the Difference Between Complete and Incomplete Antibodies?

Summary – Complete vs Incomplete Antibodies 

Antibodies play a pivotal role in a host defense mechanism and participate in protecting the host from external attack by infectious agents or foreign substances. Identification of these foreign bodies is important to avoid any clinical manifestations arising from these agents. Complete and incomplete antibodies are types of antibodies which differ in their ability and inability to participate in agglutination reactions. Due to this contrast mechanisms of complete and incomplete antibodies, the diagnostic test procedures based on these antibodies are also differed significantly. This is the difference between complete and incomplete antibody.

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Reference:

1.“Agglutination (Biology).” Wikipedia, Wikimedia Foundation, 9 Sept. 2017. Accessed 2 Oct. 2017. Available here
2.“Coombs test.” Wikipedia, Wikimedia Foundation, 13 Aug. 2017, Accessed 2 Oct. 2017. Available here

Image Courtesy:

1.’Coombs test schematic’By A. Rad~commonswiki assumed. Own work assumed (based on copyright claims). (CC BY-SA 3.0) via Commons Wikimedia