All the following are characteristics of both MHC class I and class II molecules except:
MHC class I molecules are important for which of the following?
Which of the following is incorrect concerning MHC class II molecules?
Products of TAP-1 and -2 genes
Which of the following is incorrect concerning the processing of an antigen, such as a bacterial protein, in the acid compartments of the cell?
Which of the following statements about the MHC is incorrect?
When the sequences of different MHC class I molecules are compared, the variation between molecules is concentrated within which of the following?
Answers to Review Questions
1. B MHC class I molecules are expressed on nearly all nucleated cells, but the constitutive expression of MHC class II molecules is more limited (B cells, dendritic cells, and thymic epithelial cells). MHC class II expression can be induced on other cell types (such as macrophages, endothelial cells, and human T cells) by cytokines.
2. A As described further in Chapters 9 and 10, the interaction of CD8 on the T cell and an invariant region of MHC class I molecule is crucial in the triggering of CD8+ T cells.
3 D The MHC class I molecule, not the MHC class II molecule, associates with b2- microglobulin.
4. D The products of the TAP-1 and -2 genes selectively transport peptides 89 amino acids in length from the cytoplasm into the ER where they bind to MHC class I molecules.
5. D CD8+ T cells are generally not activated by processing in acid compartments; exogenous antigen processing in acid compartments results in the generation of peptides, some of which can displace the CLIP fragment of the invariant chain from the MHC class II binding groove. The peptideMHC class II complexes move to the cell surface and can interact with a CD4+ T cell with the appropriate receptor.
6. B The b2-microglobulin gene is located outside the MHC, on a different chromosome.
7. B Regions in the binding pocket or groove that interact with peptide and the T cell receptor show the greatest variability in allelic variants.
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