7. Which one of the following mechanisms is used by human pathogens to evade host immune
responses?
(a) Somatic hypermutation (b) Antibody production
(c) Antigenic variation (d) Complement activation
Pathogens employ antigenic variation to dodge host immunity, making it the correct answer in this multiple-choice query. This SEO-optimized article breaks down the question, correct choice, and all options for biotechnology students and researchers.
Correct Answer
(c) Antigenic variation is the mechanism pathogens use to evade immunity. These organisms alter surface antigens, escaping antibody recognition and allowing reinfection or chronic persistence, as seen in trypanosomes, Plasmodium, and HIV.
Option Explanations
Each option relates to immunity but differs in pathogen versus host role.
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(a) Somatic hypermutation: This host B-cell process introduces mutations in antibody genes for higher affinity during adaptive responses, aiding pathogen combat, not evasion.
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(b) Antibody production: A core host defense generating pathogen-specific antibodies; pathogens evade it but do not employ it.
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(d) Complement activation: Host innate pathway lyses pathogens via membrane attack complexes; some microbes inhibit it, but activation harms them.
Biological Relevance
Antigenic variation involves gene switching or mutations in surface proteins, crucial for extracellular pathogens reliant on antibody evasion. Examples include Borrelia (relapsing fever) and influenza, challenging vaccine design. For biotech professionals modeling microbial kinetics, understanding this aids therapeutic development.
