A Healthy 45-Year-Old Child-Care Worker Becomes Infected with a Virus

Multiple Choice

A healthy 45-year-old child-care worker becomes infected with a virus and develops a sore throat, cough, and fever. Infected cells in the bronchial mucosa of this patient process virus-encoded proteins through an intracellular pathway and display peptides derived from the protein on the cell surface bound to class I MHC molecules. CD8⁺ T cells migrate to the mucosa and recognize these peptide-MHC complexes. Which of the following components of the TCR actually bind to the viral peptide-MHC complex?

A) Hypermutated regions: 1 in the α chain, 2 in the β chain
B) Complementarity-determining regions: 3 in the α chain, 3 in the β chain
C) Hypervariable regions: 2 in the α chain, 2 in the β chain
D) Congenic regions: 1 in the α chain, 1 in the β chain
E) One peptide-binding groove formed by the α chain and the β₂-microglobulin chain