Chapter 5 - recognition responses Flashcards
explain recognition and response by surface receptors and intracellular proteins
Surface receptors on immune cells recognize antigens (B and T cells ) or patterns (innate cells)
Activation of the receptor leads to a response
what kind of interaction do receptors interact with ligand through?
non-covalent interactions
what is the stregth quantifiable by?
the dissocaition constant
the lower the constant the higher the affinty of reaction
what is the range for enzyme ligand dissocition cosntsnt? what about for Ab Ag interactions?
10-3 to 10-5M
as low as 10-12 M
what technique is used to measure this? to dtermine antibody affinity
Equilibrium analysis
what is the difference between univalent and bivalent interactions
univalent - we have a distinch off and on
bivlaent - we have more capcity to be on in some regard
what is meant by affinty
affinity is the strength of the interaction betwee n ligand and receptor
what is avidity?
overall strength of all interactions during the multivalent binding
why woukld mutlple intracellualr pathways be actiavted?
to cause a specific response
Key steps in multiple intracellualr responses are regulated by:
phosphorlyation of proteins to form docking sites, activating enzymes, or promote degradation /stabilization of proteins
what is meant by receptor clustering?
receptor clustering allows us to actiavte signal trandusction in more receptors - multivalent ligand mediates cluster formation
Explain how membrane microdomains(lipid rafts) work
when the antigen is not present then the receptors are outside the lipid rafts
however when antigens are present these repcetors move into the raft and are close to the Lyn(throsine kinases ) allowing it to easily phosphorlayte and thus signal tranduction to occur
organisation is essential for quick activation
how can adding differnt subunits to a receptor change the affinity of the receptors for their ligand
we can increase the affinity
what kind of doamin is present on alot of recpetors?
the immunoglobulin (Ig) domain
where was the first Ig domain found?
on an antibody
