12 - LINKING 3 Flashcards
what does the TCR recognise
peptide-MHC (pMHC) complexes on the surface on the surface of APC
what does recognition of TCRs require
what is the TCR complex made of
TCR
CD3
z (zeta chain) and ITAMs
ITAM: immunoreceptor tyrosine based activation motif
intracellular signaling is triggered
structure and characteristics of a TCR recognition subunit
relative amounts of receptors in adaptive vs innate immunity
what is the reason for the huge diversity of BCR and TCR receptors
the genes undergo DNA rearrangement
the D segment is only in the beta chain
how is the functional protein made after gene rearrangement/somatic recombination
happens at the TCR genetic loci to produce a functional gene
what are the two types of APCs
professional APCs and non-professional APCs
what are professional APCs
what are non professional APCs
why are there two main types of MHCs
so that you can cover the two main types of pathogens: intracellular vs extracellular
what is MHC Class I
what is MHC Class II
what T cell does MHC Class I activate
Class I bind and present peptides generated within the cell (endogenous) and activate CD8+ T Cells (cytotoxic function)
what T cell does MHC Class II activate
binds and presents peptides of extracellular origin (Exogenous) and activates CD4+ T cells (helper)
characteristics of MHC Class I molecules
3 components required:
peptide
alpha chain
beta 2 microglobulin
characteristics of MHC Class II molecules
3 components required:
peptide
alpha chain
beta chain
(Ig) like domains in MHC
stabilised by intra chain disulfide bonds
general structural characteristics of MHC molecules
binding of peptide to peptide binding cleft in MHCI and MHCII
class I is a little bit more closed off on the sides (peptides have to be shorter)
structure of pMHC-TCR interaction
three alpha chains and beta 2 microglobulin
-> MHC class I -> CD8+ T cells
why do you need co receptors
features and structures of CD4 and CD8
what are functions of the CD4 and CD8 co-receptors
summary
