Fichas
How do we eliminate pathogens that live inside cells?
Fichas del conjunto (17)
- 1How do we kill infected cells?cytotoxic T cells (CD8+ T cells)
NK cells
macrophages - 2Describe the basics of the immune responseDC pick up bits of infection
internalize proteins and chop them up
stick peptides onto MHC surface
migrate to draining lymph nodes
MHC displayed to T cells
T cells activated
clonal expansion of T cells - 3What can be found on the surface of cytotoxic T cells?TCRab receptor
CD8 receptor - 4All cells with a nucleus have...MHC Class I molecule
when this is attached to a viral protein
this becomes activated
this interacts with CD8 receptor
followed by death by apoptosis - 5Wasps and bees - what has this got to do with killer Ts?CD8 T cells can kill repeatedly like wasps sting repeatedly without dying
whereas neutrophils die in the process of killing the invading pathogen - like a bee dies after it stings you - 6Explain how apoptosis worksnuclear blebbing - detachment of cortex from the plasma membrane
alteration in cell morphology
cell membrane remains intact
shedding of small membrane vesicles
DNA is fragmented by controlled digestion by nuclease enzymes
apoptopic bodies are removed by phagocytic cells - 7How do cytotoxic cells induce apoptosis?armed cytotoxic T cells have lytic granules (modified lysosomes)
which contain:
perforin - this modifies the target cell by forming pores in the cell membrane
granzymes - these proteases start chopping up proteins in the target cell
granulycin is also another protein - 8What is the method of killing for perforin and granzymes?the former forms pores in the cell membrane
the latter binds to proteins in the cell membrane - 9How are CD8 T cells and NK cells similar?they both secrete granzymes
- 10CD8 T cells release harmful granzymes. Why are they themselves not affected?because they have inhibitors of granzymes
these are serine protease inhibitors - 11Give an overview of how CD8 T cells kill infected cellsclonal expansion of CD8 in lymph nodes
activated CD8 leaves LN and goes to site of infection
start to bind cells with MHC attached to peptide on its surface (target cells)
kills them - 12CD8 T cells kill in a specific and directional way. Explain how they do thisCD8 grabs target cell in non-specific way
TCR:MHC:peptide interaction
smack forms
reorganisation of microtubule organising centre and Golgi apparatus
lytic granule release - 13Which immune system are NK cells considered a part of?innate immune system
- 14What are two similarties and two differences between CD8 T cells and NK cellssimilarities
-both lymphocytes
-both kill using granzymes
differences
-NK cells are a bit bigger
-NK cells have no antigen-specific receptors - 15How do activated NK cells avoid killing normal cells?missing-self hypothesis
recognition of 'self' = no killing by NKcells
recognition of 'missing self' = killing by NK cells
(if response is 'not self' or response is missing) - 16Viruses 'hide' inside normal cells- how are these infected cells killed?viruses down-regulate MHC class I
to avoid CD8 T cell
but because MHC Class I on surface is gone
nothing to respond to NK cells
killing by NK cells - 17What type of cells do NK cells and CD8 T cells kill?infected cells and tumour cells
Información
- Descripción
- University (Immunology) Fundamentals of Medicine Fichas sobre How do we eliminate pathogens that live inside cells?, creado por Ifeoma Ezepue el 04/11/2015.
- Creado por
- Ifeoma Ezepue
- Visitas
- 217
- Valoración