Many Different Viruses Encode Proteins That Function to Down-Regulate MHC

question 26

Multiple Choice

Many different viruses encode proteins that function to down-regulate MHC class I expression on host cells following infection with the virus. This immune evasion mechanism allows the virus to hide from CD8 T lymphocytes that normally detect virus-infected cells by using their T cell antigen receptor to recognize viral peptides bound to MHC class I proteins on the surface of the infected cell. To counteract this immune evasion strategy, NK cells have:

• A) Activating receptors that recognize MHC class I proteins
• B) A mechanism to secrete antiviral peptides
• C) Inhibitory receptors that recognize viral capsid proteins
• D) Activating receptors that recognize viral capsid proteins
• E) Inhibitory receptors that recognize MHC class I proteins

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Definitions:

Positive Reinforcement

A behavioral strategy that involves rewarding a behavior to increase the likelihood of that behavior being repeated.

Observational Learning

The process of acquiring new behaviors or knowledge by watching and imitating others.

Classical Conditioning

Modifying behavior by pairing a conditioned stimulus with an unconditioned stimulus to elicit an unconditioned response.

Respondent Conditioning

A form of learning in which a behavioral response is elicited by a previously neutral stimulus that has become associated with a meaningful stimulus.