Antigenic variation: Difference between revisions
Created page with "= Antigenic Variation = Antigenic variation is one method an infectious agent can evade the immune system, and is very important to extracellular [[Path..." |
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= | Antigenic variation is one method an infectious agent can evade the [[Immune system|immune system]]<span style="line-height: 1.5em; font-size: 13px;">, and is very important to extracellular </span>[[Pathogens|pathogens]]<span style="line-height: 1.5em; font-size: 13px;">, which are usually eliminated by </span>[[Antibody|antibodies]]<span style="line-height: 19.5px;"> </span><ref name="Janeway's">Kenneth Murphy (2012). Janeway's Immunobiology. 8th ed. New York: Garland Science. 510.</ref>. | ||
One type of antigenic variation is due to many [[Pathogen|pathogens]] having "a wide variety of antigenic types" (they have different serotypes) and so the body can acquire type-specific immunity to a pathogen. This means that the immune system will have antibodies that only recognise one serotype of a pathogen, and any other [[Serotype|serotype]] of that pathogen will be recognised as a unique organism by the [[Immune_system|immune system]]. Therefore the same organism can theoretically cause [[Disease|disease]] many times in the same individual.<ref name="Janeway's">Kenneth Murphy (2012). Janeway's Immunobiology. 8th ed. New York: Garland Science. 510.</ref> | |||
Another method of antigenic variation is caused by [[Point mutation|point mutations]] in the genes of a pathogen that code of an [[Antigen|antigenic feature]]. This can be things such as [[Cell surface proteins|cell surface proteins]] or the structure of [[Polysaccharide|polysaccharide capsules]]. This way, over time, an organism that an individual once had immunity to will have changed enough to no longer be recognised by the antibodies that recognised it before. This is called [[Antigenic drift|antigenic drift]] <ref name="Janeway's">Kenneth Murphy (2012). Janeway's Immunobiology. 8th ed. New York: Garland Science. 510.</ref>.<br> | |||
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Latest revision as of 09:12, 22 October 2014
Antigenic variation is one method an infectious agent can evade the immune system, and is very important to extracellular pathogens, which are usually eliminated by antibodies [1].
One type of antigenic variation is due to many pathogens having "a wide variety of antigenic types" (they have different serotypes) and so the body can acquire type-specific immunity to a pathogen. This means that the immune system will have antibodies that only recognise one serotype of a pathogen, and any other serotype of that pathogen will be recognised as a unique organism by the immune system. Therefore the same organism can theoretically cause disease many times in the same individual.[1]
Another method of antigenic variation is caused by point mutations in the genes of a pathogen that code of an antigenic feature. This can be things such as cell surface proteins or the structure of polysaccharide capsules. This way, over time, an organism that an individual once had immunity to will have changed enough to no longer be recognised by the antibodies that recognised it before. This is called antigenic drift [1].