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:
Dictionary > Antigenic variation
You will also like...

Inheritance and Probability
Gregor Mendel, an Austrian monk, is most famous in this field for his study of the phenotype of pea plants, including ..

Fruits, Flowers, and Seeds
This tutorial deals with the structure and function of flowers, fruits, and seeds. Also included here are the types of f..

Passive and Active Types of Immunity
Lymphocytes are a type of white blood cell capable of producing a specific immune response to unique antigens. In thi..

The Water Cycle
The water cycle (also referred to as the hydrological cycle) is a system of continuous transfer of water from the air, s..

New Zealand’s Unique Flora
If New Zealand has lots of unique animals, it's also got a whole lot of unique plants. Find out more about some of them,..

Plant Cells vs. Animal Cells
Plant cells have plastids essential in photosynthesis. They also have an additional layer called cell wall on their cell..