B cell differentiation

Question 1

whats required for both germinal and non germinal centres

Answer 1

CD40 signals

Question 2

what are the helper T cell in germinal centres

Answer 2

follicular T cells

Question 3

is somatic hymermutaion higher in non germinal centre or germinal centre

Answer 3

geminal

Question 4

antibodies produced where are usually better

Answer 4

germinal center

Question 5

does both the germinal centre and non-geminal centre secrete antibodies

Answer 5

yes

Question 6

do germinal center antibodies or non germinal centre antibodies have more affinity maturation

Answer 6

geminal centre

Question 7

what centre makes memory B cells

Answer 7

germinal centre

Question 8

germinal centre T cell dependent or independent

Answer 8

dependent through TFH

Question 9

B cells reply on what two cytokines to stimulate germination

Answer 9

CD40L
IL-21

Question 10

what has rapid formation (7 days)

Answer 10

germinal centre

Question 11

zones of germinal centre

Answer 11

dark
light

Question 12

whats in the dark zone

Answer 12

centroblasts that are highly proliferative germinal centre B cells

Question 13

whats in light zone (3)

Answer 13

centrocytes that are selecting germinal centre B cells
TFH cells
follicular dendritic cells

Question 14

what presents antigens to B cells

Answer 14

follicular dendritic cells

Question 15

what receptor do FDCs have

Answer 15

CR1

Question 16

AID staining reveals what part of germinal centre

Answer 16

Dark

Question 17

how does a TFH migrate into germinal centre

Answer 17

CXCR5 receptor on B cells and T cells goes to CXCL13 in germinal centre

Question 18

what does CCR7 bind

Answer 18

CCL19

Question 19

steps of germinal centre (4)

Answer 19

initiation
drak zone
light zone
cellular output

Question 20

B cell proliferation happens where

Answer 20

dark zone

Question 21

somatic hypermutation happens where

Answer 21

dark zone

Question 22

somatic hypermutation is dependent of what

Answer 22

AID

Question 23

what does somatic hypermutation do

Answer 23

leads to mutations in antibody variable regions

Question 24

what do B cells express to stay in DARK zone ? what does in=t bind

Answer 24

CXCR4 receptor to bind CXCL12 in Dark zone

Question 25

what happens to antibodies that come out of the germinal centre dark zone if there's a mutation in CXCL12

Answer 25

B cells couldn't get into dark zone so they would never get the mutations to promote better antibody production

Question 26

how do B cells migrate into light zone

Answer 26

CXCR5 on B cells get signals from CXCL13 in light zone

Question 27

what happens in the light zone

Answer 27

1. B cells test antigen binding affinity (by presentation from FDC) 2. if they are selected for ability to bind antigen (they have the antigen now) 3. then they present to TFH cells 4. TFH gives them survival signals

Question 28

what do TFH cells do to B cells

Answer 28

promote survival

Question 29

can B cells re enter the dark zone

Answer 29

yes

Question 30

2 major outputs of germinal centre reactions

Answer 30

Memory B cells Antibody secreting cells

Question 31

can memory B cells differentiate into ASCs

Answer 31

yes

Question 32

what directs isotope class switching

Answer 32

cytokines

Question 33

what isotope does IL-21 induce

Answer 33

IgG

Question 34

what isotype does IL-4 and IL-13 induce

Answer 34

IgE

Question 35

whats Produced when no class-switch signals are given

Answer 35

IgM

Question 36

IgG subclasses are good at what

Answer 36

opsonization

Question 37

what kind of isotope does IFN-y induce

Answer 37

IgG2c

Question 38

what brings about IgA

Answer 38

TGF-b

Question 39

what isotope is rarely secreted

Answer 39

IgD

Question 40

IgA does what

Answer 40

mucosal immunity

Question 41

define the process of isotope class switching

Answer 41

taking the VDJ that was made in bone marrow and wapping out the IgM for a different constant region

Question 42

goal of isotope class switching (VDJ)

Answer 42

connect VDJ to a different constant region

Question 43

does isotope class switching change the target antigen

Answer 43

no because constant region has nothing to do with the antigens

Question 44

what is AID induced by

Answer 44

Cd40 signalling

Question 45

what does AID convert

Answer 45

cytosine to uracil

Question 46

what removes the uracil by AID? what does it leave

Answer 46

UNG leaves abasic sites

Question 47

what nicks non template and template strand

Answer 47

APE1

Question 48

where does AID work

Answer 48

germinal centre

Question 49

what is sterile transcription

Answer 49

when a B cell begins transcribing an antibody constant region before it switches to that isotope

Question 50

what does AID do

Answer 50

(sterile transcription) class switch recombination somatic hypermutation

Question 51

what are AID and UNG both necessary for

Answer 51

class switch recombination somatic hypermutation

Question 52

SHM is to do what

Answer 52

increase antigen binding and affinity

Question 53

where does somatic hypermutation happen

Answer 53

variable region - specifically CDRs (where the antigen binds)

Question 54

what regions are not antigen binding

Answer 54

framework regions

Question 55

can B cells undergo multiple rounds of SHM

Answer 55

yes

Question 56

what does B cell fate (ASC or memory) rely on (2)

Answer 56

strength + duration of signal

Question 57

if a B cell receives a longer and stronger signal from a TFH cell, what happens

Answer 57

it is more likely to go to ASC

Question 58

what receptor can change during a germinal centre response

Answer 58

BCR is constantly being changed

Question 59

what transcription factor leads to germinal centre development

Answer 59

BCL-6

Question 60

what does BCR - TFH strong signal in a GC response do

Answer 60

it up regulates IRF4 and shuts off BCL-6

Question 61

IRF4 drives what progression

Answer 61

ASC

Question 62

IRF4 promotes _______ gene expression

Answer 62

Prdm1 (BLIMP-1)

Question 63

whats gene is essential for becoming an ASC

Answer 63

Prdm1 (BLIMP-1)

Question 64

Prdm1 (BLIMP-1) regulates _______

Answer 64

Xbp1

Question 65

what does XBP1 promote

Answer 65

endoplasmic reticulum expansion

Question 66

is ASC possible without Xbp1

Answer 66

no

Question 67

master transcription factor for ASCs

Answer 67

Pdrm1 (BLIMP-1)

Question 68

becoming an ASC requires continual suppression of what

Answer 68

PAX5

Question 69

what kind of cell is an ASC

Answer 69

plasma cell