Naive CD8⁺ T Cells Require Signals in Addition to T

question 10

Multiple Choice

Naive CD8⁺ T cells require signals in addition to T cell receptor recognition of peptide-MHC to become activated and differentiate into cytolytic T cells.These signals are called costimulatory signals and are provided by professional antigen-presenting cells (APCs) ,such as dendritic cells.If a virus infects epithelial cells in the respiratory tract but does not infect professional APCs,what process ensures that naive T cells specific for viral antigens will become activated?

• A)Cross-reactivity,whereby the naive CD8⁺ T cell recognizes a self antigen that is structurally similar to a viral antigen presented by dendritic cells
• B)Crossover,whereby part of the viral genome is exchanged with part of one chromosome of the host
• C)Crosstalk,whereby signals generated by the virus binding to class I MHC molecules intersect with T cell receptor signaling pathways
• D)Cross-presentation,whereby infected epithelial cells are captured by dendritic cells,and the viral proteins originally synthesized in the epithelial cells are processed and presented in association with class I MHC molecules on the dendritic cell
• E)Cross-dressing,whereby viral infection of the epithelial cell stimulates the expression of surface molecules that are typically found only on dendritic cells

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Definitions:

Variable Overhead Efficiency Variance

The difference between the actual variable overhead and the standard cost of variable overhead allocated for the actual production.

Supplies Cost

The cost associated with materials and items used in the operation or maintenance of a business or facility.

Machine-Hours

A measure of the amount of time a machine is operated, used for allocating machine operation costs to products or units produced.

Direct Labor Variances

The differences between the budgeted and actual costs of direct labor, analyzed to understand deviations in manufacturing expenses.