Some Viruses Have Mechanisms to Down-Regulate MHC Class I Protein

question 12

Multiple Choice

Some viruses have mechanisms to down-regulate MHC class I protein expression on the surface of cells in which the virus is replicating. This immune evasion strategy might prevent effector CD8 cytotoxic T cells from recognizing and killing the virus-infected cells. Would this immune evasion strategy also prevent the initial activation of virus-specific CD8 T cells?

• A) Yes, because no viral peptide:MHC class I complexes would form to activate CD8 T cells.
• B) No, because dendritic cells would take up infected cells and cross-present viral peptides to activate CD8 T cells.
• C) No, because some presentation of MHC class I complexes with viral peptides would occur before the virus could down-regulate all the surface MHC class I protein.
• D) Yes, because this immune evasion strategy would also function in dendritic cells, even if the virus doesn't replicate in dendritic cells.
• E) No, because the type I interferon response induced by the virus infection will up-regulate MHC class I expression and override the immune evasion mechanism.

Identify the criteria for the classification of investments as current assets and the valuation at fair value.

Analyze the reporting requirements for trading investments, including the treatment of dividends and gains/losses.

Distinguish between different models used for valuing non-strategic investments.

Understand the equity method and its implications for dividend income and investment account adjustments.

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Definitions:

Quasi-contract

A legal concept where a court imposes a contractual obligation on a party who didn't necessarily agree to it, to prevent unjust enrichment.

Implied-in-fact Contract

is an agreement derived from the actions, conduct, or circumstances of the parties involved, rather than from explicit written or spoken terms.

Negotiable Instrument

An official document that assures the payment of a fixed sum of money, payable either on demand or at a designated time, with the document bearing the name of the person obligated to pay.

Letter of Credit

A financial document issued by a bank that guarantees a buyer's payment to a seller within a specified timeframe.