BIOC39H3 Lecture Notes - Lecture 18: Antigenic Drift, Serotype, Epitope
8 Apr 2015
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Document Summary
Antibodies are the most important source of long-term protective immunity to many pathogens. Some species of pathogen evade such protection by existing as numerous different strains, which differ in the antigenic macromolecules on their outer surfaces. Streptococcus pneumonia: a bacterium that has different serotypes and compete with each other to infect human. Serotypes: genetic strains which differ in capsular polysaccharides, anti-body based serological assays are used to define the differences between them. After resolution of infection with a particular serotype of a bacteria, an individual would have made antibodies that prevent reinfection with that particular type but not prevent primary infection with another serotype. Original antigenic sin: phenomenon where first viral strain to infect constrains future response to other strains. In person q, mutation occurs in virus v. this antigenic drift produces virus v* with an altered hemagglutinin: neutralizing antibodies against virus v in person p do not block binding of virus v* to cells.
