A 5-year-old girl is brought to the office for evaluation of a persistent cough. The patient has had a productive cough daily for the past month. History includes recurrent episodes of otitis media despite bilateral ear tube placement, numerous lower respiratory tract infections, and occasional ulcerative skin lesions. Laboratory evaluation shows normal levels of total B and T cells and serum immunoglobulin. Genetic testing reveals a mutation in the TAP1 gene, which encodes a protein involved in the transport of cytosolic molecules into the endoplasmic reticulum. Which of the following processes is most likely to be impaired by this mutation?

Question

A 5-year-old girl is brought to the office for evaluation of a persistent cough.  The patient has had a productive cough daily for the past month.  History includes recurrent episodes of otitis media despite bilateral ear tube placement, numerous lower respiratory tract infections, and occasional ulcerative skin lesions.  Laboratory evaluation shows normal levels of total B and T cells and serum immunoglobulin.  Genetic testing reveals a mutation in the TAP1 gene, which encodes a protein involved in the transport of cytosolic molecules into the endoplasmic reticulum.  Which of the following processes is most likely to be impaired by this mutation?

Quizplus · Accepted Answer

Eductional Objective: Transporter associated with antigen processing (TAP) proteins are necessary for loading of cytoplasmic (eg, viral) proteins onto major histocompatibility complex (MHC) class I molecules. The MHC class I-peptide complex can then activate CD8⁺ cytotoxic T cells through interaction with the T cell receptor and CD8 coreceptor.

A 5-Year-Old Girl Is Brought to the Office for Evaluation