Immunity: Chapter 04, Adaptive Immunity and the Detection of Infection by T Lymphocytes

Table of Contents

1. 4-1 Dendritic Cells in the Induction of Adaptive Immunity
2. 4-2 The Structure and Function of MHC Molecules
3. 4-3 The MHC and Polymorphism of MHC Molecules
4. 4-4 Non-Classical MHC Class I Molecules
5. 4-5 Peptide Binding by MHC Molecules
6. 4-6 Antigen Presentation by Classical MHC Class I Molecules
7. 4-7 Antigen Presentation by MHC Class II Molecules
8. 4-8 Regulation of Antigen Presentation
9. 4-9 Specialized Features of Antigen Presentation by Dendritic Cells

4-9 Specialized Features of Antigen Presentation by Dendritic Cells

Work through the following questions, checking all the correct answers. For each question there may be more than one correct answer.

1

Which of the following statements are true? a) Levels of cell-surface expression of MHC class II molecules are kept low in immature dendritic cells by low expression of CIITA. b) Levels of cell-surface expression of MHC class II molecules are kept low in immature dendritic cells by rapid internalization of surface MHC class II molecules. c) Levels of cell-surface expression of MHC class II molecules are kept low in immature dendritic cells by retention of MHC class II molecules in the endosomal compartment by the invariant chain. d) Levels of cell-surface expression of MHC class II molecules are kept low in immature dendritic cells by rapid degradation of proteins in the endosomal-lysosomal system. e) Phagocytosis is rapidly upregulated by dendritic cells in response to infectious agents and inflammatory cytokines. f) Phagocytosis is downregulated in mature activated dendritic cells. g) Cross-presentation is a process in which cytosolic proteins are transported into the endosomal-lysosomal system. h) Cross-presentation is a process whereby CD8 T cells recognize peptide-MHC class II complexes. CorrectWrong: b, c, e, and f are true.Your answer has been saved.

2

The degradation of proteins in the endosomal-lysosomal system is especially highly regulated in dendritic cells because: a) ingested infectious organisms must be destroyed by them. b) degradation of the invariant chain is required for peptide loading and progression to the cell surface by MHC class II molecules. c) it is important that the range of antigenic peptides available for loading on MHC class II molecules be maximized. CorrectWrong: b and c are correct.Your answer has been saved.

3

The major pathway of cross-presentation of peptides by dendritic cells involves: a) targeting of newly synthesized MHC class I molecules to the endosomal-lysosomal system. b) degradation of internalized proteins by the proteasome. c) transport of peptides derived from internalized proteins into the endoplasmic reticulum lumen by the TAP transporter. d) generation of peptides from internalized proteins that have the same properties as peptides generated from cytosolic proteins. CorrectWrong: b, c and d are correct.Your answer has been saved.