Cell Mediated (I)

Question 1

What is cell mediated immunity called

Answer 1

Adaptive transfer of immunity via cells not serum

Question 2

Which types of antigens does T cell recognise

Answer 2

Cell associated

Antigenic peptides on MHC

Question 3

What are the 2 ways T cells work

Answer 3

Cytotoxic to kill viruses

Th to modulate macrophages and B cells

Question 4

Explain the 4 domains of a TCR on T cells

Answer 4

V alpha V beta

C alpha C beta

2 chains

Question 5

How are alpha and beta in Tcr linked

Answer 5

Disulfide bond

Question 6

Explain the structure of MHC class I

Answer 6

Alpha 3 domains (A1,2,3)

1 beta2 microglobulin

1 transmembrane domain

Question 7

What makes up the MHC 1 peptide binding cleft

Answer 7

Alpha 1 and 2

Question 8

How is MHC II different to MHC I

Answer 8

1 alpha chain (A1,2)

1 beta chain (B1,2)

2 transmembrane domains

Question 9

What makes up MHC II binding cleft

Answer 9

A 1, B 1

Question 10

Which cell types are MHC 1 on compared to MHC 2

Answer 10

MHC 1- on all cell types

MHC 2- APC (b cells, dendritic, macrophages)

Question 11

Which type of antigen do MHC 2 on apc act on

Answer 11

Extracellular (not made by own cell)

Question 12

How is extracellular antigen taken up and presented by MHC 2 on apc cells

Answer 12

Into vesicles via endocytosis

Fusion with endosome causes acidification

Professes cleave antigen into peptides

Fragmented peptide vesicles fuses with vesicles with MHC II in them

Question 13

What happens when dendritic cells engulf extracellular pathogens then present them on their MHC 2

Answer 13

Go to the lymphatic system into lymph nodes and causes activation of T cells

Question 14

Which infections do MHC 1 take care of

Answer 14

Intracellular pathogens

Question 15

What do MHC 1 with intracellular pathogens/ endogenous antigens bind to

Answer 15

CD8 cytotoxic receptors

Question 16

How do CD8 kill intracellular pathogens from MHC 1 recognition

Answer 16

Granzymes and perforin

Apoptosis of infected cell

Question 17

Which MHC interaction causes autoimmune response in diabetes to kill B cells

Answer 17

MHC 1 and CD8

CD8 causes apoptosis of B cells in pancreas

Question 18

How do CD4 Th cells mediate other cells

Answer 18

Cytokines

Question 19

What do Th cells leave thymus as and when do they differentiate into 5 types

Answer 19

Th 0

Differentiate when come into contact at lymphatic organs via MHC II

Question 20

What do TH1 do (type 1 response)

Answer 20

Bind to MHC II on macrophages

Stimulates macrophages and phagocytosis/ inflammation

Question 21

Which cytokine is released by th 1 to stimulate NK and macrophages and more th1 production

Answer 21

IFN - y

Question 22

What is Th2 cells for

Answer 22

Kill EC pathogens by attracting eosinophils, mast cell stimulation (b cells activated to produce igE)

Question 23

What is main cytokine in type 2 response which allows class switching to IgE to activate mast cells / basophils

Answer 23

IL 4

Question 24

Does IL 4 also stimulate th2 production

Answer 24

Yes

Question 25

Which Th cells release IL 17 when they recognise MHC II

Answer 25

Th17

Question 26

What is the action of IL 17 release by Th17

Answer 26

Acts on Stroma cells to secrete chemokines (attract neutrophils for inflammation)

Acts on epithelial cells to release AMPs

Question 27

What do TFh cells release (follicular)

Answer 27

IL 21

Question 28

What does IL 21 do by tfh release when MHC II detected

Answer 28

Stimulate differentiation of B cells, class switching and antibody release from plasma cells

Question 29

Which Th cell is involved in type 1 and 2 response

Answer 29

Tfh

Question 30

What does T Reg do

Answer 30

Prevents autoimmunity or stimulation of T cells via MHC II

Question 31

Give example of cytokines released by t reg to stop immunity

Answer 31

TGF, IL 10