Exam 5: Antigen Recognition by T Lymphocytes

Explain specifically how interferon-γ produced during an infection enhances (A)antigen processing in the MHC class I pathway,and (B)antigen presentation in the MHC class II pathway.

(i)Describe the structure of an MHC class I molecule,identifying the different polypeptide chains and domains.(ii)What are the names of the MHC class I molecules produced by humans? Which part of the molecule is encoded within the MHC region of the genome? (iii)Which domains or parts of domains participate in the following: antigen binding; binding the T-cell receptor; and binding the T-cell co-receptor? (iv)Which domains are the most polymorphic? B.Repeat this for an MHC class II molecule.

Cross-priming of the immune response occurs when _____.(Select all that apply.)

A. Describe in chronological order the steps of the antigen-processing and antigen-presentation pathways for intracellular, cytosolic pathogens. B. (i) What would be the outcome if a mutant MHC class I α chain could not associate with β2-microglobulin, and (ii) what would happen if the TAP transporter were lacking as a result of mutation? Explain your answers.

Identify which features of the RAG genes have similarity to the transposase gene of transposons. B.Explain how the mechanisms for immunoglobulin and T-cell receptor rearrangement may have evolved in humans.

Which of the following statements regarding CD8 T cells is incorrect?