C3 cell mediated immunity

Question 1

what is a cell mediated response

Answer 1

is any that involves cells
resident cells at the site of entry- and then innate response recruits cells to infection site
innate and specific cells are involved

Question 2

antibody based effector responses

Answer 2

aggluntination
antibody mediated cytotoxicty

Question 3

innate and specific cells used in cell mediated immunity

Answer 3

-innate
NK cells, granulocytes, phagocytic cells, mast cells, basophils
-specific cells
direct effect-cytotoxic t cells
indirect via mediators produced ig IFNy, TNF

Question 4

innate cell recogniton

Answer 4

pathogen-associated molecular patterns (PAMPs) interact with pathogen recognition receptors (PRR)

Question 5

specific B/T cell recognition

Answer 5

aa sequence of proteins
antibody:antigen binding/T cell receptor binding

Question 6

cell types and functions of effector module cytotoxicty

Answer 6

NK cells, CD8 T cells
elimination of virally infected and metabolically stressed cells

Question 7

cell types and functions of effector module intracellular immunity (type 1)

Answer 7

ILC1, Th1 cells
elimination of intracellular pathogens, activation of macrophages

Question 8

mucosal and barrier immunity (type 2) cell types and funtions

Answer 8

ILC2, Th2 cells
elimination and expulsion of parasites, recruitment of eosinophils, basophils and mast cells

Question 9

extracellular immunity (type 3) cell types and functions

Answer 9

ILC3, Th17 cells
elimination of extracellular bacteria and fungi, recruitment and activation of neutrophils

Question 10

what cells can bring about phagocytosis

Answer 10

macrophages or netrophils

Question 11

summary of phagocytosis

Answer 11

engulf pathogen in phagosome, get induction of respiratory burst, generation of superoxide
lysosomes fuse with phagosome- phagolysosome- enzymes digest pathogen

Question 12

what are the toxic products produced by phagocytosis

Answer 12

nitric oxide and hydrogen peroxide

Question 13

what happens to the rate of phagocytosis when target is opsonised

Answer 13

enhanced (>4000x)

Question 14

what cells contain granules

Answer 14

granulocytes, eosinophils, neutrophils, basophils, mast cells, NK cells

Question 15

what do granules contain

Answer 15

proteins which recruit other immune cells to site
eg mast cells produce leukotriene B4

Question 16

perforins action on target cells

Answer 16

aids in delivering the contents of granules into cytoplasm of target cell

Question 17

granzymes action on target cell

Answer 17

serine proteases, which activate apoptosis once in the cytoplasm of target cell

Question 18

granulysins action on target cell

Answer 18

has antimicrobial actions and can induce apoptosis

Question 19

what do cytotoxic cells lyse

Answer 19

lyse body’s own cells- gets rid of abnormal cells or pathogen-infected cells
do not directly lyse pathogen

Question 20

what is recognition of cytotoxic cells dependent on

Answer 20

dependent on amount of MHC expressed (NK cells) or engagement or T cell receptor and antigen presented on MHC mols on target cell
Fas ligand interaction with Fas on target cell

Question 21

what is required for cytotoxic cells to carry out their function and why

Answer 21

close contact with target- immunological synapse
formation of central superpolarised activation complex and granules pass through to immunological synapse

Question 22

how fast is the delivery of granules

Answer 22

rapid
polarisation of lytic granules in cell before exocytosis takes 50-500 secs. avg 200

Question 23

how many types of granzymes do humans have compared to mice

Answer 23

human- 4
B A K M
mice- 10

Question 24

what is activated by death signal causing apoptosis, and how many types

Answer 24

activates caspase cascade, at least 12 types of caspases

Question 25

what are the three types of pathogen recognition receptors on NK cells

Answer 25

1. killer immunoglobulin-like receptor (KIR)
2. heterodimeric C-lectin receptors (CD94 and NG2)
3. natural cytotoxicty receptors

Question 26

how do cytotoxic T cells know the cell they are killing

Answer 26

target expresses the antigen that matches the specificity of the TCR
granules are induced AFTER stimulation or direct death

Question 27

cytotoxic t lymphocyte mechanism summary

Answer 27

CTL recognises and binds virus infected cell
CTL programs target for death, inducing DNA fragmentation
CTL migrates to new target
Target cell dies by apoptosis