Dictionary > Antigenic variation

Antigenic variation

Definition
noun, plural: antigenic variations
(immunology) The changing of surface proteins by an infectious agent to evade a host immune response
Supplement
Antigenic variation is one of the ways by which an infectious agent evades a host immune response. For example, a pathogenic bacterium could alter its surface proteins and carbohydrates so as to circumvent the immune response of the host.
Antigenic variation makes the pathogen evade detection of the immune cells by altering their surface antigens. This gives the pathogen the advantage of repeatedly infecting the same host (re-infection) and therefore prolongs its stay within the host. It also increases the chance of being transmitted to a new host.
One of the immune responses of the host is to detect the surface antigens of the pathogen. Once detected, the immune cells would target the pathogen and destroy it. Some immune cells, such as B cells, produce antibodies that could detect and incite destruction of pathogens that bear similar antigens in case of re-exposure. However, certain pathogens are capable of antigenic variation and therefore would render the antibodies ineffective against them.
Some of the mechanisms employed to enable antigenic variation are gene conversion, site-specific DNA inversions, and hypermutation.
See also:


You will also like...

Cells in different stages of meiosis
Meiosis – The Genetics of Reproduction

Meiosis is a form of cell division that creates gametes. It is comprised of two divisions that in the end, the resulting..

Fossil trilobite imprint in the sediment
Insects

There are more species of insects than any other species combined. This surely illustrates that insects have the selecti..

The Human Physiology
The Human Physiology

Physiology is the study of how living organisms function. Thus, human physiology deals specifically with the physiologic..

Energy pyramid
Freshwater Community Energy Relationships – Producers & Consumers

This tutorial looks at the relationship between organisms. It also explores how energy is passed on in the food chain an..

Selective Breeding
Selective Breeding

Gregor Mendel's studies into Monohybrid and Dihybrid crossing and Charles Darwin's study of evolution and natural select..

Biological Cell Defense
Biological Cell Defense

Organisms employ different strategies to boost its defenses against antigens. Humans have an immune system to combat pat..

Related Articles...

No related articles found

See all Related Topics