Chapter 5 Flashcards
Antigen Recignition by T Lymphocytes
Is TCR similar to BCR
yes
what does TCR have that BCR does now
alpha chain beta chain that does antigen binding
does tcr have a transmembrane region
yes
the red part on the t cell binds both what
MHC and peptide
does TCR undergo VDJ recomincation
yes
what are the two classes of t-cell receptor
alpha beta
gamma delta
gamma is equivalent to alpha which is equivalent to
light chain
delta is equivalent to beta which is equivalent to
heavy chain
where is the delta chain located on tcr
in between v and j
if the alpha chain starts the process it kicks out what chain entirely
delta
what do gamma delta tcrs bind
glycolipids presented by CD1 molecules instead of peptides presented on MHC
are b cells or t cells more diverse
t cells
total diversity is added afterwards with what
somatic hypermutation
TCR=
binding domain
what is the signal domain
CD3 and zeta chain
do you need both zeta and CD3 to work
yes
major histocompatibility complex genes encoded in the
human leukocyte antigen locus
the whole region is
HLA locus
class II HLA involves what
MHCII and other genes involving Ag processing and presentation
class I HLA encodes what
MHCI genes
MHCI is on all
nucleated cells
are red blood cells nonucleated
yes
what is present to CD8 and T cells
MHCI
what helps with intracellular infection/ antigens
MHCI
in MHCI Ag are broken down in
cytoplasm
professional Ag- presenting cell is what complex
MHCII
MHCII recognizes what
B cells
macrophages
dendritic cells
what is present to CD4 (helper) T cells
MHCII
what has antigens from extracellular infections
MHCII
in MHCII Ag are broken down in
endosomes (phagosome)
TCRs bind both what
MHC and antigen
CD T cell recognizes viral antigens presented by …
MHC class I on virus-infected cell
CD8 T cells does what to the virus-infected epithelial cell
kills
CD4 T cell recognizes bacterial antigens presented by…
MHC class II on a macrophage
what does CD4 T cell secrete that activate the macrophage, increasing its capacity to kill bacteria
cytokines
CD4 T cell recognizes bacterial antigens presented by MHC class II on a
B cell
CD$ T cells secretes cytokines that drive the differentiation of the B cell into a….
plasma cell making bacteria-specific antibodies
Co- receptors bind what domain of MHC molecules
Ig-like
target cell of CD8 T cell binds
alpha 3
antigen presenting cell of CD4 T cell binds
beta 2
emoty MHC molecule has what kind of binding
promiscuous
what does promiscuous binding mean
MHC molecule bind in non-sequence specific manner which binds multiple peptides
MHC class I and bound peptide has what kind of conformatioin
closed
does MHC class I and bound peptide have open or closed ends
closed
what is the limit size of mhc class I and bound peptide
8-10 aa
MHC class I and bound peptide has anchor residues at 2/9 of peptide and these bind
2 a.a. on MHC in groove
MHC class II and bound peptide has what type of conformation
open ends
length of MHC class II and bound peptide
10-25 a.a. in length
about how many a.a in groove and where do the rest go?
about ten a.a. and the rest hang over
how many residues of the peptide that bind a.a. in the groove
3-4
basic antigen processing and presentation MHC I
- Ag in cytoplasm
- breakdown antigen
- load into MHC
- present peptide to a T cell
basic antigen processing and presentation MHC II
- Ag taken up
- break down Ag
- Ag loaded onto MHC II
in basic antigen processing and presentation MHCII, antigen is taken up from extracellular space into
intracellular vesiscles
in basic antigen processing and presentation MHCII, in early endosomes of neutral pH, what are inactive
endosomal proteases
in basic antigen processing and presentation MHCII, acidification of vesicles activates proteases to degrade antigen into
peptide fragments
in basic antigen processing and presentation MHCII, vesicles containing peptides fuse. with
vesicles containing MHC class II
3 steps in AG for NHC I antigen processing and presentation
- cell infected
- Ag will be broken down by immunoproteosome
- TAP will transport peptides from cytoplasm to ER
3 steps in MHC for MHC I antigen processing and presentation
- MHC is translated and sent to the ER
- MHC assemble w/ calnexin as chaperone from beta-2 microglobin
- MHC assembles the peptide loading complex MHC+ calreticulin+ tapasain+ ERP57
step, 4,5,6, for MHC I antigen processing and presentation
- peptide loading complex sample peptides that enter ER-> pick peptide that is good fit
- ERP57 will trim the peptide down to 8-10 aa
- MHC and peptide will get secreted to cell surface
what is immunoproteosome induced by
IFNdelta
what do immunoproteosome generate
peptides that are 8+ aa w hydrophobic basic a.a. @ c terminus
what does ERP57 do
trim