Transcript Macaque models for HIV/M.tb Studies.

Antigen presentation to T cells
Zheng W. Chen, M.D., Ph.D
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
Ag presentation pathways
Typical MHC class I pathway for antigen peptide
processing and presentation (occuring in ER)
MHC class II pathway for antigen peptide processing and
presentation (occurring in the vesicle)
MHC class II molecules in the ER cannot bind to peptides in the ER because newlysynthesized MHC class II molecules are associated with the invariant chain (Ii) that fills
and blocks their peptide-binding groove.
Peptides that bind to MHC class II molecules are generated
in acidified endocytic vesicles.
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