lecture 12-B cell activation and Ab production

Question 1

what is the activation of B cells initiated by

Answer 1

specific recognition of Ags by the surface BCRs

Question 2

what are humoral immune responses initiated by

Answer 2

recognition of Ags by specific BCR on B lymphocytes

Question 3

what is the primary immunoglobulin in a primary response

Answer 3

IgM

Question 4

what type of cells are the majority of mature naive B cells

Answer 4

follicular B cells

Question 5

what chemokine guides the movement of B cells

Answer 5

CXCL13

Question 6

what are large antigens delivered by

Answer 6

subcapsular sinus macrophages or by DCs in the medulla

Question 7

how are most antigens from tissue sites transported to LNs

Answer 7

afferent lymphatic vessels that drain into the sub capsular sinus of the LNs

Question 8

what type of DCs capture blood-borne pathogens

Answer 8

plasmacytoid DCs

Question 9

what are polysaccharide Ags captured by

Answer 9

macrophages in the marginal zone of splenic lymphoid follicles and displayed or transferred to B cells in this area

Question 10

what type of antigens to follicular B cells response to

Answer 10

protein antigens

Question 11

what are T-independent responses to multivalent Ags mediated mainly by

Answer 11

marginal zone B cells in the spleen and B-1 cells in mucosal sites

Question 12

what is another name for conventional B cells

Answer 12

B-2 B cells

Question 13

what do B-1 B cells arise from

Answer 13

fetal liver

Question 14

what type of Ab responses do not need Ag-specific helper T cells

Answer 14

those to multivalent non-protein Ags with repeating epitopes (polysaccharides, some lipids, and nucleic acids)

Question 15

what is the main producer of BAFF

Answer 15

myeloid cells in lymphoid follicles in the bone marrow

Question 16

what is the initial signal for activation of follicular B cells

Answer 16

BCR signaling that initiates the process of B cell activation

Question 17

what is the second signal for activation of follicular B cells

Answer 17

BCR internalizing the bound Ag into endosomal vesicles

Question 18

what co receptor on B cells facilitates activation of B cells

Answer 18

CR2/CD21

Question 19

what cell is CD40 located on

Answer 19

B cells

Question 20

what T cell helps in the follicular/germinal center

Answer 20

Tfh cells in germinal center

Question 21

where are short-lived plasma cells located

Answer 21

extrafolilicular

Question 22

what transcription factor is in the extra follicular zone

Answer 22

blimp-1

Question 23

what transcription factor is in the follicular/germinal center

Answer 23

Bcl-6

Question 24

what sequential activation does the generation of Tfh cells require

Answer 24

first by DCs and then by activated B cells.

Question 25

what interleukins do Tfh cells secrete

Answer 25

IL-21, IFN-gamma, IL-4

Question 26

what interleukins control isotope switching

Answer 26

IFN-gamma and IL-4

Question 27

what interleukin is required for GC development and generation of plasma cells

Answer 27

IL-21

Question 28

what draws Tfh cells into the lymphoid follicles

Answer 28

CXCL13

Question 29

what do TFH cels express

Answer 29

ICOS, PD_1, cytokien IL-21 and Bcl-6

Question 30

what does the dark zone contain

Answer 30

proliferating B cells, stained with an anti-Ki67 Ab, which detects cycling cells

Question 31

what does the light zone contain

Answer 31

follicular DCs stained with an anti-CD23 Ab

Question 32

what does the alternative processing of primary RNA transcript result in

Answer 32

formation of mRNA for the membrane or secreted form of the mu heavy chain

Question 33

where does isotope switching primarily occur

Answer 33

GCs and driven by Tfh cells

Question 34

what does class switching occur in response to

Answer 34

changing the constant regions of the heavy chains

Question 35

what determines Ab specificity

Answer 35

variable regions

Question 36

what is BAFF produced by and what Ig does it costimulate switching to

Answer 36

produced by DCs and macrophages and costimulates switching to IgA

Question 37

what are isotope switching and affinity maturation critical dependent on

Answer 37

AID

Question 38

where does CSR take place

Answer 38

activated B cells

Question 39

what does CSR result in

Answer 39

looped out deletion of the intervening DNA segments

Question 40

what is AID expression activated mainly by

Answer 40

CD40 signals from Tfh cells

Question 41

what is required for somatic hypermutation of IgV genes to be initiated

Answer 41

Tfh cells and CD40:CD40L interactions

Question 42

where are mutations mostly clustered

Answer 42

V regions (mostly in the Ag-binding complementarity-determining regions

Question 43

where do B cells that have undergone somatic mutation migrate to

Answer 43

migrate into FDC rich light zone of GC

Question 44

what are B cell lymphomas caused by

Answer 44

chromosomal translocation of various oncogenes into Ig gene loci

Question 45

what are plasma cells maintained by

Answer 45

BAFF

Question 46

describe most TI Ags

Answer 46

multivalent (composed of repeated identical Ag epitopes)

Question 47

what cells are particularly important for Ab responses to TI Ags

Answer 47

MA and B1 cells

Question 48

where are B1 cells mainly

Answer 48

peritoneum and mucosal sites

Question 49

where are MZ B cells and what do they primarily respond to

Answer 49

Spleen: polysaccharides

Question 50

what are the most important TI Ags

Answer 50

polysaccharides, glycolipids, nucleic acids

Question 51

what is the dominant Ab class induced by pneumococcal capsular polysaccharide

Answer 51

IgG2

Question 52

define conjugate vaccines

Answer 52

polysaccharide is covalently linked to a foreign protein to form the equivalent of a hapten-carrier conjugate

Question 53

what does the fab region include

Answer 53

entire V and C regions of the light chain

Question 54

what mechanism is most responsible for coexpression of IgM and IgD on the surface of B cell clones

Answer 54

alternative RNA splicing

Question 55

multiple myeloma is a cancer which has arisen from____

Answer 55

plasma cell

Question 56

where are CDRs found and what do they do

Answer 56

determine antibody specificity and found on both the heavy and light chains

Question 57

if you wanted to check for the presence of memory B cells from your vaccine subjects by taking some of their B cells and restimulating them in vitro with antigen, the best place to get some memory cells would be from____

Answer 57

bone marrow