cell mediated response Flashcards
explain how t cells are activated?
inflammation - more fluid made
dendritic cells pick up debris, become activated APCs
forced down the afferent lymphatics to the lymph nodes
find T cell to activate
activated T cell undergoes clonal expansion
what is another name for cytotoxic t cells?
cd8 t cells
which mhc class presents to cytotoxic t cells?
mhc class I
what do cytotoxic t cells do?
they kill tumour cells and infected cells
in what form can t cells recognise proteins?
on mhcs as APCs
describe the process by which t cells kill a cell?
virus injects rna/dna into cell, viral proteins made non-self peptide on the mhc class 1 molecule cell makes intererons t cells detect this non-self peptide, bind to it and triggers apoptosis
describe the steps of apoptosis
nuclear blebbing
change in morphology - inside breaks down, membrane is intact
shedding of small vesicles
dna is digested by nucleases
apoptotic bodies removed from phagocytic cells
what do lytic granules contain?
perforin and granzymes
what does perforin do?
forms pores in the membrane
what do granzymes do?
proteases cleave proteins
describe how t cells use lytic granules to induce apoptosis
non-specific adhesion of T cells to body cells to check for the non-self antigen
TCR:MHC peptide interaction
Forms a seal/chute
microtubule organisation centre and golgi rearranged
lytic granules released
apoptosis
what do nk cells stand for?
natural killer cells
are nk cells part of the adaptive or the innate immune response?
innate
what type of cells are NK cells?
lymphocytes
why dont nk cells have the ability to detect pathogens?
they dont have antigen specific receptors on their surface
