Antigen Processing/Presentation Flashcards
pattern recognition receptors
mannose receptors
scavenger receptors
toll-like receptors
the process of taking up a microbe, processing the antigens and presenting it to a naive T cell
antigen processing and presentation
primary antigen-presenting cells (professional APC)
dendritic cells
dendritic cells are ____ cells and are the link between ___ and ____ immunity
phagocytic; innate; adaptive
dendritic cells typically express ____ molecules and present antigen peptides within ____ on surface
MHC II; MHC II
monocytes in blood become ____ in tissue; they are ____ cells extremely important for the clearance of _____
macrophages; phagocytic; dead cells and debris
moncytes/macrophages are extremely important for ____
antigen presentation
B cells are ___, part of ____ immunity; they can activate ____(more common in secondary or memory immune responses)
lymphocytes; adaptive
T cells
antigen presentation is a way to concentrate the antigen in areas most likely to come into contact with ____ and ____
T cells; B cells
steps to antigen presentation
- microbe infects host
- microbe is taken up by APC at site of infection
- APC enters lymph circulation and into LN
- Naive T and B cells enter LN from circulation
antigen presenting cells are not limited to ____, ____, and ____; all nucleated cells can present endogenous antigens in association with ____ molecules
dendritic cells; macrophages; B cells
MHC I
the original function of the MHC (major histocompatibility complex) was linked only to ____
graft rejection
MHC was later found to be of critical importance to all ____ involving _____
immune responses; protein antigens
MHCI is found on all ____ cells; ____ protein can bind to MHCI ; MHCI is recognized by ____
found on all nucleated cells
cytoplasmic (intracellular)
CD8+ T cells (cytotoxic T cells)
MHC II is found on ____; ____ proteins bind to MHC II; MHC II is recognized by ____
antigen presenting cells
extracellular
CD4+ T cells (helper T cells)
the process by which antigens are digested and placed on the cell surface with the correct MHC molecule
antigen processing
2 pathways of antigen processing
- extracellular proteins that are internalized by professional APCs into vesicles are processed and displayed by class II MHC molecules
- proteins in the cytosol of nucleated cells are processed and displayed by class I MHC molecules
degradation of cytoplasmic proteins
cytoplasmic proteins (intracellular) > proteasome > peptides > exopeptidase > amino acids
degradation of endocytic proteins (extracellular)
endocytic proteins > lysosome > peptides > exopeptidase > amino acids
MHC II is synthesized in the ____, packaged into a vesicle in the ____, and then transported to the ____ and fuses with it
ER; golgi; phagolysosome
processed peptide binds to the ____ of MHC II
binding groove
often cytosolic proteins are ____ proteins; during ___ and ____ there are these proteins in the cytoplasm
viral; entry/uncoating; reassembly
proteins in the cytoplasm that are not used by the cell get tagged for ____; ____ binds to the proteins which targets them to the ____ to be cleaved into smaller peptides
degradation; Ubiquitin; proteasome
Peptides are transported into the endoplasmic reticulum through the _____
TAP transporters (transporter associated with antigen processing)
Peptide that is transferred into the ER by TAP is trimmed to the correct size by an_____ called ____.
The correct size peptide can then bind to the binding groove of _____
aminopeptidase; ERAP; MHCI
The antigen bound to MHCI can be a ____ or it can be a ____ peptide (i.e., from a protein from the host cell). This is one way in which the immune system is supposed to recognize self vs. non-self
foreign protein/peptide; self
antigen presentation is central to the development of the ____
immune response
Antigen presentation bridges ____ by innate immune system to the _____ of the adaptive immune system
antigen recognition; activation
antigen presentation is necessary for _____ and augments ____
T-cell mediated killing; antibody production by B cells
antigen processing and presentation is essential but not sufficient for…?
activation of naive T cells
CD8+ T cells are ___ restricted and recognize ____
MHC I; cytosolic proteins
CD4+ T cells are ____ restricted and recognize ____
MHC II; extracellular and intravesicular pathogens
The ____ recognizes antigen, but it does not signal
T cell receptor (TCR)
____ and ____ are non-covalently associated to the TCR
CD3; zeta
expression of the ___, ___, and ____ chain are required for antigen recognition and signaling
TCR; CD3; zeta
___ recognizes antigen, while ___ and ____ signal
TCR; CD3 and zeta
recognition of antigen and MHC molecule in the absence of co-stimulation fails to activate the T cell and leads to…?
anergy of the T cell
at the termination of the immune response, ___ replaces ____ and downregulates T cell function
CTLA-4; CD28
____ play a role in activating T cells AND terminating the T cell response
B7 molecules
before T cell activation ____ on T cell recognizes ___ on antigen presenting cell
CD28; B7 receptor
at termination of immune response, ____ on T cell interacts with ____ on APC to downregulate T cell function
CTLA-4; B7 receptor
____ can competitively inhibit CD28 binding to B7
CTLA-4
CTLA-4, when bound to B7, will actively block signals from the ____ and from ____
TCR; CD28
