A) Macrophage
B) Dendritic cell
C) Endothelial cell
D) B lymphocyte
E) Epithelial cell
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A) Display major histocompatibility complex (MHC) -associated peptides on their cell surfaces for surveillance by B lymphocytes
B) Initiate T cell responses by specifically recognizing and responding to foreign protein antigens
C) Display MHC-associated peptides on their cell surfaces for surveillance by T lymphocytes
D) Display polysaccharide antigens on their cell surfaces for surveillance by B lymphocytes
E) Secrete peptides derived from protein antigens for binding to T cell antigen receptors
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C
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A) At least equal to the number of complexes of self peptides with class II MHC on the cell surface
B) Greater than 10³
C) Less than or equal to 0.1% of the total number of class II MHC molecules on the cell surface
D) Greater than 10⁶
E) Zero
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C
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A) Class II MHC and costimulators
B) Class I MHC and CD4
C) Class II MHC and CD8
D) CD4 and costimulators
E) Class II MHC and CD4
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A) Viral infections are cleared by antibodies, not T cells.
B) The patient's own immune system would destroy the transfused T cells before they could respond to the viral infection.
C) T cells recognize peptides, not viral particles.
D) Donor T cell viral antigen recognition is restricted by MHC molecules not expressed in the patient.
E) In responding to the previous infection, the donor would have used up all his T cells specific for that virus.
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A) Cross-reactivity, whereby the naive CD8⁺ T cell recognizes a self antigen that is structurally similar to a viral antigen presented by dendritic cells
B) Crossover, whereby part of the viral genome is exchanged with part of one chromosome of the host
C) Crosstalk, whereby signals generated by the virus binding to class I MHC molecules intersect with T cell receptor signaling pathways
D) Cross-presentation, whereby infected epithelial cells are captured by dendritic cells, and the viral proteins originally synthesized in the epithelial cells are processed and presented in association with class I MHC molecules on the dendritic cell
E) Cross-dressing, whereby viral infection of the epithelial cell stimulates the expression of surface molecules that are typically found only on dendritic cells
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A) Immature dendritic cells are ubiquitously present in skin and mucosal tissues.
B) Dendritic cell maturation occurs after migration to lymph nodes in response to signals derived from activated T cells.
C) Class II MHC and T cell costimulators are highly expressed on immature dendritic cells and are down-regulated during maturation.
D) Dendritic cells that enter lymph nodes through draining lymphatics migrate to the B cell-rich follicles in response to chemokines.
E) The principal function of mature dendritic cells is antigen capture.
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A) Response to the vaccine requires T cell recognition of complexes of the viral peptide with HLA-DR, but the peptide cannot bind to the allelic variant of HLA-DR found in the nonresponders.
B) The nonresponders could not express class II MHC proteins.
C) The viral peptide is not an immunodominant epitope.
D) The nonresponders underwent determinant selection of another viral epitope.
E) Because of technical errors, the nonresponders had not received adequate doses of the vaccine.
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A) Encoded by a viral gene
B) Present in an acidic vesicular compartment of the APC
C) Present in the cytosol of the APC
D) Internalized into the cell from the extracellular space
E) Small in size
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A) In response to interferon-ƴ secreted during the innate immune response to the virus, the mucosal epithelial cells express class II MHC, with bound viral peptides, on their cell surfaces.
B) Mucosal epithelial cells, like all nucleated cells, express class I MHC molecules and are able to process cytoplasmic viral proteins and display complexes of class I MHC and bound viral peptides on their cell surfaces.
C) Antibodies specific for viral antigens bind to these antigens on infected cell surfaces and engage Ig Fc receptors on the CTL, thereby targeting the CTL to the infected cells.
D) Virus-infected mucosal epithelial cells migrate to draining lymphoid tissues, where they present viral peptide antigens to naive CD8⁺ T cells.
E) Viral infection of the mucosal epithelial cells stimulates them to express E-selectin, which promotes CD8⁺ T cell adhesion.
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B
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A) By ATP-dependent transport via the transporter associated with antigen-processing (TAP) 1/2 pump
B) By passive diffusion
C) By receptor-mediated endocytosis
D) Through membrane pores
E) Via the proteasome
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A) Calreticulin
B) Nuclear factor (NF) -ĸB
C) Tapasin
D) Ubiquitin
E) Calnexin
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A) Adjuvants induce local inflammation, thereby increasing the number of antigen-presenting cells (APCs) at the site of immunization.
B) Adjuvants stimulate the expression of costimulators on local APCs.
C) Adjuvants enhance local production of cytokines that promote T cell activation.
D) Adjuvants prolong the expression of peptide-MHC complexes on the surface of APCs.
E) Adjuvants bind to T cell antigen receptors and promote their proliferation.
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A) β₂-Microglobulin
B) Cathepsin
C) Invariant chain
D) HLA-DM
E) Calnexin
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A) Macrophages are particularly important at presenting peptides derived from particulate or opsonized antigens that are internalized by phagocytosis.
B) Macrophages become activated by the helper T cells to which they present microbial peptides, and as a result of this activation they become efficient at killing the microbes.
C) Resting macrophages express low levels of class II MHC molecules, but higher class II MHC expression is induced on activation by the T cells to which they present antigen.
D) Macrophages express highly variable, high-affinity receptors for many different antigens, and these receptors facilitate the internalization of the antigens for processing and presentation.
E) Macrophages present antigen to T cells in lymphoid organs and many nonlymphoid organs.
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A) Self proteins are not presented by the class I pathway because only microbial proteins, and not self proteins, are ubiquinated in the cytosol.
B) Peptides derived from self proteins are not presented by the class I or class II pathways because MHC molecules are expressed only in response to infections.
C) Self proteins are not presented by the class II pathway because endosomal acidic proteases digest microbial proteins but not eukaryotic proteins.
D) Self peptide/self MHC complexes are formed and displayed by antigen-presenting cells in both class I and class II MHC pathways, but T cells that recognize these complexes usually are not present or are functionally inactive.
E) Peptides derived from self proteins are not displayed by MHC molecules because they usually are displaced by the more abundant microbial peptides.
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A) Follicles
B) High endothelial venules
C) The medullary sinus
D) T cell zones
E) Efferent arterioles
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