1.5 T-cell diversity Flashcards
(22 cards)
TCR structure
- 2 component membrane bound molecule
- alpha and beta chain
- variable region
- constant region
TCR requires ______ to enable signaling
additional signaling (delta, gamma, zeta, epsilon)
CD3 marker is used to recognize ______
T-cells
what do T-cells genomic structures consist of?
variable regions, joining regions, diversity regions,
what happens with the T-cells genome?
-somatic recombination
- formation of T-cell receptor genes
(doesnt go any further after this)
Delta/gamma is in _____ concentration than alpha/beta and is found in the ____ tissue.
lower, gut epithelium
does gamma/delta TCR display MHC restrictions?
NO!
what does TCR need to bind?
MHC molecule and antigen
CD8 binds to ____ of MHC __
CD4 binds to ____ of MHC __
alpha, MHC1
Beta, MHC2
CD8 deals with _____ pathogens and CD4 deals with ____ pathogens
intracellular, extracellular
MHC1 can be seen on _____ while MHC2 can be seen on _____
-MHC1: all nucleated cells except RBC
- MHC2: B-cells, macrophages, dendritic, thymic epithelium
Difference in peptide binding between MHC1 and MHC 2?
MHC1:
- binds peptides 8-10AA long
- both ends of AA attached
-ERAP removes peptides so its right length for MHC1
MHC2:
-peptides 12-15AA long
- both ends are floppy
Intracellular pathogen loading for MHC1
MHC1 heavy chain stabilized by calnexin → B2-microglobulin binds → calnexin released → complex formed → TAP delivers peptides → MHC 1 exported to ER
antigen loading for MHC2
Invariant chain blocks peptide binding to MHC2 in ER → invariant chain cleaved, CLIP fragment bound → CLIP blocks binding of peptides → HLA-D makes CLIP release → peptides can bind to MHC2
Polymorphic huaman MHC1 isotopes
HLA-A, B, C
Oligomorphic human MHC1 isotopes
HLA-E/G
Monomorphic human MHC1 isotopes
HLA-F
For transplants these alleles must match:
Homozygous: __ Class 1, ___ Class 2
Heterozygous: __ Class 1, ___ Class 2
Homo: 3,3
Hetero, 6,16
RAGs play a role in recombination by _____
cutting out loops of information, then reconnecting the original sequences
what is the Theory of evolution of RAG activity?
The RAG proteins have been proposed to originate from a transposable element (TE) as they share mechanistic and structural similarities with several families of transposases and are themselves capable of mediating transposition.
What is the exact opposite of how transposition works?
somatic recombination
for antimicrobial peptides to be able to make a pore, they must have what types of interactions?
electrostatic, hydrophobic
