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.

Apply mathematical formulas to compare investment returns and assess financial choices.

Perform calculations involving rate adjustments, such as inflation and discount rates, on financial planning.

Evaluate the financial implications of deferring payments or restructuring payment schedules.

Assess financial plans and payment options in consideration of inflation rates and expected investment returns.

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Definitions:

Rejecting Null Hypothesis

The decision in hypothesis testing that the evidence is strong enough to conclude a significant effect exists.

Retaining Null Hypothesis

The decision in hypothesis testing that there is not enough evidence to reject the null hypothesis, implying the observed data does not significantly differ from what was expected.

Alpha (α)

Alpha (α) represents the level of significance in hypothesis testing, defining the threshold for rejecting the null hypothesis.

Critical Value

A critical value is a point on the distribution that represents a threshold above which significant results are considered to occur.