Macaque models for HIV/M.tb Studies.

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Antigen presentation to T cells Zheng W. Chen,
M.D., Ph.D
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Intracellular compartments in APC for generation
of TCR ligands (MHC-peptide complexes)
Cytosol the compartment for MHC class I Ag
presentation pathway viruses and some bacteria
can replicate in cytosol. Their Ag peptides
bound to MHC class I and presented to TCR on CD8
T cells. Vesicular system MHC class II
Ag presentation pathway extracellular material
(microbes) is taken out by endocytosis into
endosomes, which then move to lysosome for
degradation, bond to MHC class II, and presented
to TCR on CD4 T cells
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Ag presentation pathways
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Typical MHC class I pathway for antigen peptide
processing and presentation (occuring in ER)
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MHC class II pathway for antigen peptide
processing and presentation (occurring in the
vesicle)
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MHC class II molecules in the ER cannot bind to
peptides in the ER because newly-synthesized MHC
class II molecules are associated with the
invariant chain (Ii) that fills and blocks their
peptide-binding groove.
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Peptides that bind to MHC class II molecules are
generated in acidified endocytic vesicles.
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Question

• An patient with influenza virus infection was
  found to
• have viremia and influenza virus-infected
  dendritic
• cells. The patient would have
• A. viral peptide-specific antibodies only
• B. viral peptide-specific CD8 T cells only
• C. viral peptide-specific CD4 T cells only
• D. both viral peptide-specific CD4 and CD8 T
  cells