fundementals of immunology - Revision

Question 1

what are the T cell receptor segments for each of the receptor chains?

Answer 1

Alpha chain - V, J, C
Beta chain - V, D, J, C
Complementarity determining regions between these genes CDR1,2,3 for both alpha and beta chains.

No Somatic hypermutation for T cells, CDR1 & 2 is limited to germline V chains. CDR3

Question 2

How (where) does the T cell and TCR development take place

Answer 2

develop in bone marrow, mature in thymus

First attempt to make a beta chain and test it against a mock alpha chain. then create an alpha chain to create a functional TCR

Question 3

Somatic recombinatioin. Proteins involved

Answer 3

RAG, TdT, artemis

Question 4

The function of CD25

Answer 4

Interleukin 2 receptor alpha chain. important for T cell proliferation and activation. It is activated as part of further activation (signal 3) when a TCR recognises antigen.

CD25 high indicates T regs

Question 5

Type 1 responce, targets and function

Answer 5

microscopic intracellular

killing infected cells

Question 6

Type 2 responce. Target and function

Answer 6

Macroscopit (parasites)

killing/expelling parasites

Question 7

Type 3 responce. Target and function

Answer 7

Microscopic extracellular (fungi, bacteria).
finding, capturing and killing pathogens

Question 8

How do CD4 cells help, 1) B cells,

2) innate responces and 3) CD8 cells

Answer 8

1) induce class switching and plasma cell formation.
2) induce polarization and maturation of innate cells.
3) regulates expansion and memory potential.

Question 9

T helper cell subsets

Answer 9

Th1, Th2, Th17, Tfh, Treg

others: Th9, Th22

Question 10

Th1 polarizing cytokine

Answer 10

IFN-gamma

IL12

Question 11

TH2 polarizing cytokine

Answer 11

Il-4

Question 12

TH17 polarizing cytokine

Answer 12

TGFbeta
IL-6
IL-23
(maintains polarization by secreting IL-21)
effector:IL-17

Question 13

Treg polarizing cytokine

Answer 13

TGFbeta

IL-10

Question 14

Tfh polarizing cytokine

Answer 14

IL-21

IL-6

Question 15

TH1 functions

Answer 15

Activates macrophages. + MHC1.

defence against intracellular pathogens.

Question 16

TH2 functions

Answer 16

Activate eosinophils.

Defence against extracellular pathogens (helminths)

Question 17

TH17 functions

Answer 17

Activate Neutrophils. Activate epithelium.

Defence against extracellular pathogens. (Bacteria & Fungi)

Question 18

Tfh functions

Answer 18

Activate B cells. Increase antibody affinity (SHM)

Question 19

Treg functions

Answer 19

Regulate T cell priming and function.

Prevent auto immunity. Promote cancer.

Question 20

TH1 killing functions

Answer 20

activate macrophages (CD40L) to destroy engulfed bacteria.

Kills chronically infected cells-then engulfed by macrophages

Question 20

TH1 proliferative functions

Answer 20

T-cell proliferation (il-2)

macrophage differentiation in BM (IL3 and GM-CSF)

Question 21

TH1 - macrophage associated functions

Answer 21

induce macrophage binding to endothelium and exit from blood vessel (TNFalpha/beta)

macrophages accumulate at site of infection (CCL2)

Question 22

TH2- parasite expelling functions

Answer 22

Activate mast cells and eosinophils to promote histamine release - expel pathogen.

activate goblet cells to produce mucus

class switch to IgE

Question 23

TH2 chemokine production

Answer 23

Type 2 chemokines:

il4, 5, 9, 13

Question 24

TH17 pathogen location

Answer 24

mainily at mucosal surfaces.

Question 25

TH17 functions of cytokine production

Answer 25

il17 via cxcl8 recruit neutraphils il22 enhance epithelial barrier function and activates specialised epithelial cells (panth cells) which have antimicrobial function.

Question 26

Transcription factor for TH1

Answer 26

Tbet

Question 27

Transcription factor for TH1

Answer 27

Tbet

Question 28

Transcription factor for TH2

Answer 28

GATA3

Question 29

Transcription factor for TH17

Answer 29

RORgammaT

Question 30

TH17, 2 step differentiation process

Answer 30

Differentiation - TGF-beta and IL-6 lead to RORgammaT transcription - RORgammaT produces IL-17, and IL-23 leads to amplification of the cells Stabilization - STAT3 and RORgammaT act as transcription factors to produce TH17 cel

Question 31

TH2 during a viral infection

Answer 31

will aquire TH1 like functions such as upregulation of T-bet. simultaneous to GATA3

Question 32

The B cell receptor structure

Answer 32

The BCR is an Ig (IgD, IgM, IgA, IgG, or IgE) associated with a CD79 molecules (alpha & beta chains) which has ITAM (immunoreceptor tyrosine-based activation motif) components.

Question 33

B cell and BCR development

Answer 33

B cell develops in bone marrow. Initial rearrangment of genes to form a heavy chain (pro-lymphocyte) then rearrangement of the light chain (pre-lymphocyte). Initial stages are antigen independent. but then undergo self antigen exposure.

Question 34

Somatic recombinatioin. Proteins involved

Answer 34

RAG complex (RAG1 and RAG2) Enzyme targetting specific sequences (recombination signal sequences) at the ends of VDJ chains. either 12bp targets or 23bp targets. Both T and B cells

Question 35

CD79 (Ig alpha/beta)

Answer 35

CD79 or Ig (CD79 alpha & beta/Ig alpha & beta) is associated with Ig B cell receptors (BCR) and contains an ITAM for intracellular signalling on antigen recognition