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...

An artist's depiction of the origin of amphibians
Amphibians & Early Reptiles

Obtaining air outside an aquatic environment required species to acquire suitable adaptations, and this was the case of ..

Selective Breeding
Selective Breeding

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

dinosaurs
The Dinosaurs

Dinosaurs represented a major turn in the evolutionary development of organisms on Earth. The first dinosaurs were presu..

New Zealand - Biodiversity fauna
New Zealand’s Biodiversity

Find out more about New Zealand's unique biodiversity by exploring a range of different ecosystems and the key role of s..

Oligodendrocyte and Schwann cell
The Central Nervous System

Myelin sheath is essential for a faster conductivity of signals. Know more about this feature of some neurons in the Cen..

Muscle
Muscle

Muscle cells are specialized to generate force and movement. Learn about the different types of muscle tissues in this t..