Once Expressed on the Surface of Host Cells, an MHC

question 10

Multiple Choice

Once expressed on the surface of host cells, an MHC protein remains stably associated with its bound peptide for several days. This highly stable peptide binding behavior is important because:

• A) It prevents peptide exchanges on the cell surface, ensuring that peptide:MHC complexes are reliable indicators of the proteins present inside that host cell.
• B) If the MHC protein lost its peptide it would become unstable, and would be rapidly internalized and degraded.
• C) Pathogens would otherwise evade the immune response by making decoy peptides that mimic host cell peptides.
• D) Pathogens would be able to evade the T cell response by making proteases that cleave MHC proteins inducing peptide release.
• E) Immune responses to infection often induce noxious chemicals that damage surface MHC proteins, and might result in peptide loss.

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Definitions:

Myelin

A fatty substance that surrounds and insulates the axons of many neurons, enhancing the speed of electrical impulses.

Pudendal Nerve

A nerve in the pelvic region that carries sensory and motor information to and from the genitalia and surrounding areas.

Spinal Nerves

Nerves that branch out from the spinal cord, transmitting motor, sensory, and autonomic messages between the body and the spinal cord.

Cranial Nerves

Twelve pairs of nerves that emerge directly from the brain, not the spinal cord, serving head and neck functions.