Immunology 5 Flashcards
What percentage frequency are TCRs alphabeta heterodimer (as opposed to gammadelta)?
90%
Which of the following characteristics belong to TCRS:
a) long cytoplasmic domains
b) membrane bound
c) Secretory
d) short cytoplasmic domain
e) No cytoplasmic domain because its secreted
b) membrane bound
d) short cytoplasmic domain
What does TCR recognise?
Antigen as a complex of antigen peptide fragment with self MHC molecule
TCR have CDR like domains. True or false?
True
The TCR gene loci (alpha, beta, gamma, delta) is arranged very similarly to that of WHAT?
Immunoglobulin.
The arrangements of α/gamma loci are equivalent to the light chain and the arrangement of beta/delta are similar to the heavy chain.
Do the alpha/gamma chain gene loci have V, D and J or V and J?
V and J (and C)
Do the beta/delta chain gene loci have V, D and J or V and J?
V, D and J (and C)
Junction diversity happens in the genes for which molecules?
TCR and immunoglobulin
recombination signal sequences, 12/23 rule, RAG1-2 complex all the same
TCR has somatic mutation. True or false?
False, because no AID is expressed!!!
Why is it advantageous for T cell not to undergo somatic mutations?
To prevent cytotoxic cells adapting to recognise epitopes presented on healthy cells.
What is CD3?
CD3 is the signalling complex which is the characteristic marker of T cell
How many subunits exist in the TCR signalling complex?
8
1 dimer in the TCR - alpha/beta
2 CD3 dimers - epsilon/delta gamma/epsilon
1 CD247 dimer - zeta/zeta (which exists primarily in the cytoplasm)
What are ITAMs?
Immunoreceptor tyrosine activation motifs which are involved in signalling.
In T cell co-stimulation what does B7 on the APC bind to?
CD28 on the T cell
What does CD28 binding to B7 lead to?
An activation signal which causes the T cell to make a cytokine called IL-2 (interleukin 2) which is a cytokine that drives proliferation of T cell, which can acts on itself and other T cells.
