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?

Question

Quizplus · Accepted Answer

Each$\alpha$ and $\beta$  chain of the T cell receptor (TCR)contains both a constant and a variable domain.The variable domain contains short stretches of amino acids where the variability between different TCRs is concentrated,and these form the hypervariable or complementarity-determining regions (CDRs).Three CDRs in the $\alpha$chain are juxtaposed to three similar regions in the $\beta$  chain to form the part of the TCR that specifically recognizes peptide-MHC complexes.The variable regions of Ig molecules may undergo hypermutation during humoral immune responses,but this does not happen in TCRs.Congenic does not refer to a part of a protein,but rather to an inbred strain of animal.Peptide-binding grooves are part of MHC molecules,not TCRs.

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

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