B cell activation

Question 1

Primary immune responses occur

Answer 1

in secondary lymphoid tissues

Question 2

B cell activation is initiated

Answer 2

in the outer areas of follicles in primary immune responses

Question 3

antigen crosslinks

Answer 3

to mIG on b cell which upregulates BR3

Question 4

antigen mIG complex is

Answer 4

endocytosed and undergoes peptide MHC class II expression on B cell surface

Question 5

BR3 interaction with Blys is

Answer 5

critical for survival of the B cell because it escapes apoptosis

Question 6

B cell receptors that interact with T cell

Answer 6

HLA class II/peptide, HLA class II, B7-1(CD80) B7-1 (CD86), LFA-3 ICAM-1,2, CD40 L

Question 7

T cell receptors that interact with B cells

Answer 7

TCR, CD4, CD28 CD2, LFA-1, CD 154

Question 8

Hyper IgM syndrome

Answer 8

patient only has IgM

Question 9

Thp in interfollecular region leads to

Answer 9

Th1 and Th2 cells, Cd40 L is expressed and sytokines secreted

Question 10

Cognate interaction is

Answer 10

the acrtivation of B cells by way of all the receptors.

Question 11

after dissassociation of B cells and T cells

Answer 11

the B cells clonally expand

Question 12

Some B cells turn into

Answer 12

plasma cells that secrete IgM for 4 days post immunization

Question 13

Other B cells do

Answer 13

isotype switch 10-14 dyas post immunization

Question 14

plasma cells secrete

Answer 14

higher affinity antibodies

Question 15

some B cells become

Answer 15

long lived memory B cells that ciruclate in immunosurveillance

Question 16

down regulation of B cells and Plasma cells happens when

Answer 16

IgG’s bind low affinity Fc-Gamma Rs on B cells and plasma cells and they eventually undergo apoptosis

Question 17

BR3 is upregulated on B cells following

Answer 17

antigen crosslinking of B cells mIg

Question 18

BLyS is produced by

Answer 18

activated monocytes, macrophates, and dendritic cells

Question 19

BLyS release is triggered by

Answer 19

cytokine acting on the cells or by IgG-FcGamma R signallng

Question 20

BLyS binds to BR3 and leads to

Answer 20

B cell survival

Question 21

abnormal production of BLyS allows

Answer 21

survival of autoreactive b cells

Question 22

high serum levels of BlyS have been reported in

Answer 22

patients with rheumatoid arthiritis, SLE and multiple sclerosis

Question 23

Typically proteins, B cell activation requires

Answer 23

CD4+ T cell cytokines and cognate interaction

Question 24

Haptens are

Answer 24

often chemical or degradation products less than 5kD

Question 25

Haptens immunogenic when

Answer 25

coupled to large proteins and they become the epitope

Question 26

Effecti=

Answer 26

carrier effect because large protein carrier of hapten

Question 27

T independent antigens induce

Answer 27

naive B cell activation without T-B cell contact mainly saccharides

Question 28

T-independent antigens lead to

Answer 28

mainly the production of IgM (LPS, Peuomococcal polysaccharide

Question 29

Mitogens trigger

Answer 29

proliferation of many clones of lymphocytes

Question 30

B cell mitogens

Answer 30

pokeweed mitogen (PWM) and HIgh Lipopolysaccharide(LPS)

Question 31

T cell mitogens

Answer 31

concanavalin A (Con A) Phygohemagglutinin( PHA), PWM

Question 32

Com A and PHA are

Answer 32

plant glycoproteins called Lectins that bind carb molecules

Question 33

Superantigens

Answer 33

often bacterial products that activate subsets of T cells

Question 34

Superantigens bind

Answer 34

specifically to regions of the T cell receptor called V beta

Question 35

Activation of all T cell clones that express any V-beta lead to

Answer 35

excesive amount of cytokines being released

Question 36

effect of excess cytokines is called

Answer 36

cytokine storm

Question 37

IgG B cells can either

Answer 37

become a memory cell with sIgG or a plasmacell that secretes IgG

Question 38

Memory cells usually express

Answer 38

high affinity immunoglobulin and isotypes other than IgM.

Question 39

entry of memory cells into the lymphoid tissue happens at

Answer 39

the HEV High endothelial venules