Question

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

Answer 1

The activation of naive CD8+ T cells specific for viral antigens, when professional APCs are not infected by the virus, is carried out through cross-presentation by dendritic cells.

Step-by-step explanation:

If a virus infects epithelial cells in the respiratory tract but does not infect professional antigen-presenting cells (APCs), the process that ensures that naive T cells specific for viral antigens will become activated is known as cross-presentation.

During cross-presentation, dendritic cells capture infected epithelial cells, process the viral proteins, and then present them on their surface associated with class I MHC molecules.

This method allows dendritic cells to activate naive CD8+ T cells, enabling them to differentiate into cytotoxic T lymphocytes (CTLs), which can then target and destroy cells infected with the virus.