2.4 Flashcards
how are T cells in lymphoid organs alerted when there is an infection
APC are captured and processed and the antigens are transported to T cells
antigens are transported from ___ to ___ where recognition by __ occurs
- tissue / mucosa
- lymphoid organs
- T cells
what resides in tissues and captures microbes and antigens
dendritic cells
___ are drained via lymphatic vessels or enter blood stream
cell-free antigens
the majority of DC in tissues and lymphoid organs are ___
classical DC
classical DC are in the ___
t cell zone of lymph nodes
___ capture and process protein antigens
immature dendritic cells
DC are activated via ___ and migrate to lymph nodes via ___
- PRR
- chemokine gradient
chemokine gradient is produced by the upregulation of ___ and ___
- chemokine receptors (CCR7)
- costimulatory molecules
___ present protein antigens to T cells
mature DC
what determine the specific recognition of antigens by T cells
major histocompatability complex (MHC) molecules
MHC molecules display ___ derived from ___
- peptides
- protein antigens
___ on T cells recognize ____ displayed by ___ on APC
- T cell receptors
- peptide antigens
- MHC molecules
what are human MHC proteins called
human leukocyte antigens (HLA)
what are the 2 sets of highly polymorphic genes
- Class I MHC genes
- Class II MHC genes
___ & ___ are susceptibility factors for periodontitis
- HLA-A9
- HLA-B15
what is the structure of MHC class I molecules
- membrane proteins containing a peptide-binding cleft at the amino-terminal
- alpha chain associated with beta 2 - microglobulin with a groove accomodating 8-9 aa peptide
what is the structure of MHC class II molecules
- membrane proteins containing a peptide-binding cleft at the amino terminal
- alpha & beta chains with a groove accomodating 10-30 aa peptide
CD8 T cells only recognize peptides presented by ___
MHC class I
how are peptides recognized by CD8 Tcells
the alpha 3 binds CD8 on CD8 Tcells
CD4 T cells only recognize peptides presented by ___
MHC class II
how are peptides recognized by CD4 T cells
beta 2 binds CD4 on CD4 T cells
what do MHC polymorphisms ensure
that a population can deal with microbe diversity
what are MHC class II expressed on & induced by
- APC
- IFN gamma
what are MHC class I expressed on
all nucleated cells
MHC molecules only bind ___
peptides derived from protein antigens
T/F one APC can display multiple peptides
true
how are proteins converted into peptides?
antigen processing pathways
what are the 3 steps of extracellular protein processing
1 - antigen internalization
2 - antigen degradation in lysosome
3 - antigen (peptide) association with Class II molecules in endosome
extracellular proteins are processed in ___ & peptides are displayed on ___ to ___
- endosome / lysosome
- MHC class II
- CD4 cells
cytosolic proteins are processed by ___ & peptides are displayed on ___ to ___
- proteasome & endoplasmic reticulum
- MHC class I
- CD8 cells
what are the 3 steps of cytosolic protein processing
1 - antigen degradation by proteasome
2 - peptide transport via TAP in ER
3 - antigen (peptide) association with class I molecules
what is the significance of MHC-associated antigen presentation
optimization of response to different microbes in different locations
extracellular microbes are associated with __
CD4 T cells
intracellular microbes are associated with ___
CD8 T cells
MHC molecules only bind ___
protein antigens
MHC I molecules are composed of ___ & ___ and bind to __
- alpha chain
- beta-microglobulin
- CD8
MHC II molecules are composed of ___ & ___ and bind to
- alpha chain
- beta chain
- CD4
how are extracellular proteins processed for presentation to T cells?
a - processed in the endosome/lysosome and loaded onto MHC class II for presentation to CD4 T cells
b - processed in the endoplasmic reticulum and loaded onto MHC class II for presentation to CD8 T cells
c - processed in the endoplasmic reticulum and loaded onto MHC class I for presentation to CD4 T cells
d - processed in the endosome and loaded onto MHC class II for presentation to CD8 T cells
a - processed in the endosome/lysosome and loaded onto MHC class II for presentation to CD4 T cells
what statement concerning antigen processing and presentation is correct?
a - class II molecules are composed of one beta2-microglobulin and one alpha chain
b - CD8 T cells recognize peptides associated with MHC class II
c - MHC locus consists of two sets of non-polymorphic genes
d - peptides bind outside of the cleft of MHC class I & II molecules
e - CD8 T cells recognize peptides associated with MHC class I
e - CD8 T cells recognize peptides associated with MHC class I
what statement below reflects accurately antigen presentation to T cells?
a - neutrophils present antigen bound to TLR to T cells
b - B cells present antigen bound to BCR to T cells
c - macrophages present antigen bound to scavenging receptor to T cells
d - DC present antigen bound to MHC molecules to T cells
e - DC present antigen bound to microglobulin to T cells
d - DC present antigen bound to MHC molecules to T cells
