2.4 - B Cell Immunity

Question 1

Important cytokines in activation of B cells

Answer 1

IL-4, IL-6 and IL-10

Question 2

IL-6 and IL-10 play a role in what

Answer 2

the differentiation of B cells to antibody secreting plasma cells

Question 3

When B cells proliferate, they can turn into

Answer 3

Memory cells and plasma cells

Question 4

Major antibody secreting cell

Answer 4

Plasma cell

Question 5

Yes or no for these scenarios with B cells and plasma cells: Surface Ig, Surface MHC class II and high rate of Ig secretion

Answer 5

B cells: Yes, Yes, no
Plasma cells: no, no, yes

Question 6

Where does the B cell encounter the T cell?

Answer 6

Lymph node

Question 7

Mature naive B cells goes to primary follicle, which then goes to ___ to look for antigen

Answer 7

FDC

Question 8

B cell recognizes ___ portion of antigen

Answer 8

native

Question 9

T cell recognizes ___ portion of antigen

Answer 9

processed

Question 10

FDC expresses what receptor that C3b can bind to and remain on the cell surface

Answer 10

CR1 receptor

Question 11

When the B cell and TfH CD4 positive T cells interact, where will they go?

Answer 11

• Some go to medullary cords to differentiate into plasma cells
• Others go back to primary follicle, actively divide w/ the formation of the germinal center

Question 12

Somatic hypermutation occurs in what region

Answer 12

V region

Question 13

Describe somatic hypermutation

Answer 13

B cells are trying to end up w/ high affinity antibodies that bind tighter
- If they have low affinity they undergo apoptosis

Question 14

Apoptosis of low affinity antibodies after somatic hypermutation are engulfed by

Answer 14

Tingible body macrophages

Question 15

IL-10 and IL-6 specific function

Answer 15

Make antibodies that fight and terminate current infection

Question 16

IL-4 specific function

Answer 16

• Bring about differentiation into memory B cells

Question 17

T independent antigen do/don’t require the presence of a helper T cell

Answer 17

Don’t

Question 18

T-independent antigens contain ___ that provide both signals 1 and 2

Answer 18

repetitive epitopes

Question 19

Examples of repetitive epitopes

Answer 19

lipopolysaccharides and capsular polysaccharides

Question 20

Is there class switching in t-independent antigens? Why? What’s the major antibody class?

Answer 20

No, b/c T cells are responsible for class switching and you don’t have T cells present
IgM

Question 21

Majority of antigens encounter T dependent or T independent antigens

Answer 21

T dependen antigens

Question 22

cytokines play a role in what in T-dependent response

Answer 22

Play a role in which antibody isotype switching may occur

Question 23

IL-4 induces ___ production

Answer 23

IgE

Question 24

TGF-beta induces ___ production

Answer 24

IgA

Question 25

Describe IgM

Answer 25

- macroglobulin - Mainly found within vascular system - defense against bloodborne pathogens - bacteremias

Question 26

All polymeric antibodies have J chains, including ___ and ___

Answer 26

IgM and IgA

Question 27

Describe IgG

Answer 27

- major antibody class in blood and within tissues - protects newborn b/c only class to cross the placenta - protects against blood borne and tissue associated infections

Question 28

Subclasses of IgG

Answer 28

IgG1 IgG2

Question 29

Half life of IgG is

Answer 29

1 month

Question 30

IgG1 function

Answer 30

response to protein antigens

Question 31

IgG2 function

Answer 31

response to carbohydrate antigens

Question 32

What happens when there's an in utero infection?

Answer 32

- fetus can make IgM and IgG - can make high concentration of IgM (it'll respond to infectious agent)

Question 33

At birth, how long are babies protected from infection? Then what happens?

Answer 33

5-6 months Then newborns start to make antibodies and their levels are low

Question 34

___ receptor is responsible for transporting IgG from blood to tissue and for crossing the placenta

Answer 34

FcRn

Question 35

IgD function

Answer 35

No function

Question 36

IgE function

Answer 36

- associated w/ allergic reactions - important in parasitic infections

Question 37

IgE receptor

Answer 37

FcepsilonRI

Question 38

IgA function

Answer 38

- major antibody in external secretions - protects mucosal surfaces

Question 39

___ plays a role in active transport and has a protective effect in external secretions

Answer 39

secretory piece (SC)

Question 40

___ can go through same process as IgA in patients that lack IgA

Answer 40

IgM

Question 41

Steps for IgA binding to poly Ig receptor

Answer 41

1. binding 2. endocytosis into epithelial cell 3. transported across cell and released through lumen of secretory gland 4. receptor cleaved and IgA is bound to mucus through secretory piece

Question 42

saliva contains what Ig

Answer 42

sIgA

Question 43

gingival exudate has what Ig

Answer 43

- mainly IgG - but also has IgM and IgA

Question 44

Gingival or cervicular fluid IgG to IgA ratio

Answer 44

More IgG than IgA and has high ratio

Question 45

Saliva ratio of IgA to IgG

Answer 45

19:1

Question 46

___ can degrade S-IgA1 and make it nonfunctional

Answer 46

IgA protease

Question 47

Describe Neutralization and what's their Ig

Answer 47

antibody that neutralizes viruses or bacterial toxins IgA and IgG

Question 48

Opsonization Ig

Answer 48

IgG

Question 49

Sensitization for killing by NK cells Ig

Answer 49

IgG

Question 50

Sensitization of mast cells Ig

Answer 50

IgE

Question 51

Describe the Activates complement system and what's their Ig

Answer 51

also called lysins cause disruption of cell membranes, especially in conjunction w/ the C system IgM and IgG

Question 52

Describe agglutinins and their Ig class

Answer 52

enhance bacterial removal IgM

Question 53

Describe opsonins and their Ig class

Answer 53

enhance phagocytosis IgG

Question 54

Phagocytic cells have what 2 receptor types?

Answer 54

Fc and C3b (CR1 or C3b receptor)

Question 55

Describe anti-adherence and what's their Ig class

Answer 55

- prevents attachment of microbes to cells or hard surfaces - sIgA in saliva

Question 56

4 common Fc receptors

Answer 56

FcRn FclambdaRI FclambdaRIII (CD16) FcepsilonRI

Question 57

Antibody dependent cell cytotoxicity involves NK cells which have ___ receptor

Answer 57

CD16

Question 58

Anti-CD20 is used today of part of ___

Answer 58

Targeted therapy in treating patients w/ B cell leukemias and lymphomas

Question 59

receptor for IgE. What's the receptor expressed by?

Answer 59

FcepsilonR1 Mast cells and basophils and eosinophils