b cell activation

Question 1

what is first ig produced in immune response ?

Answer 1

igM

Question 2

what is most abundant Ig in the blood, lymph and tissues?

Answer 2

igG

Question 3

The _____________ is mediated by B-2 B cells binding to TD antigens.

Answer 3

T-dependent response

Question 4

_____________ express _____________ concentrations of transcription factors known to be important in the maintenance of the cellular resting state (quiescence); they are therefore more effectively “poised” to enter the cell cycle.

Answer 4

memory B cells; lower

Question 5

affinity

Answer 5

strength of binding of 1 Fab region and the antigen; usually high for bi-valent ig

Question 6

avidity

Answer 6

total affinity of 1 antibody

Question 7

where does SHM occurs?

Answer 7

Dark zone

Question 8

what regulates class switch recombination? this causes a change in _____

Answer 8

Cytokines released by T-cells. Change in isotype produced by B cell.

Class switch recombination (CSR) is instigated by activation-induced cytidine deaminase (AID), which converts cytosines in S regions to uracils. The uracils are subsequently removed by two DNA repair pathways, resulting in mutations, single-strand DNA breaks, and the double-strand breaks required for CSR.

Question 9

igM is a _____ where each monomeric unit is joined by _______

Answer 9

pentamer, disulfide bonds

Question 10

igM is found in _____ and its function is to ? (Theres 3 mentionned)

Answer 10

blood
most efficient ig for activating complement system
ag agglutination
natural antibodies
low affinity since it doesnt need class switch recombination to form

Question 11

igG has the ______ half life and has _____ subclasses
also is important in what function?

Answer 11

longest, four
agglutination (neutrilizes toxinx, immobilizes bacteria, neutralizes viruses)
opsonization
ADCC
Activates complement
Produced in memeory response

Question 12

what Ig is able to cross the placenta ?

Answer 12

igG is passed to newborns via colostrum

Question 13

what ig is produced in memory response ?

Answer 13

igG

Question 14

what Ig is major in secretions (mucus, saliva, treas, milk)?

Answer 14

igA

Question 15

igA exists as a ______ in secretions and ______ in serum

Answer 15

dimer; monomer

Question 16

igA has ______ subclasses and is important asa primary defense against :

Answer 16

two
local respiratory or gastro-intestinal infections

Question 17

what ig functions in phacocytosis, agglutination, prevents attachement to epithelial surfaces , ACDCC and degranulation?

Answer 17

igA

Question 18

activated B-cells are called:

Answer 18

centroblast

Question 19

proliferating B cells are called

Answer 19

centrocytes

Question 20

of all ig’s, _____ has the shortest half life and is in lowest conc. in the serum

Answer 20

igE

Question 21

what ig plays an important role in protection against parasites, and has an FC region with high affinity to receptors on mast cells and basophils ( allergen)?

Answer 21

igE

Question 22

what ig is found in upper respiratory tract secretions?

Answer 22

igD

Question 23

what two ig binds to mast cells and basophils?

Answer 23

igD and IgE

Question 24

what ig’s are coexpressed on the surface of mature, naive B cells?

Answer 24

igM and IgD where igD>igM

Question 25

upon binding of antigen, this ig causes increase release in antimicorbial peptides and cytokines

Answer 25

igD

Question 26

when igE + allergen complex bind to the Fc receptor specific for igE on a mast cell, _______ causes the release of granule contents such as _______ that mediate allergic reactions

Answer 26

degranulation;histamine

Question 27

what reactions involve Fc receptors binding to Fc domains of Abs?

Answer 27

transcytosis, ADCC, Opsonization and phagocytosis, activation of complement. degranulation

Question 28

in class switch recombination, what makes double-strand breaks in the switch (S) region?

Answer 28

AID (activation induced deaminase)

Question 29

differential RNA processing determines whether igM or igD is expressed since

Answer 29

cells cannot switch from igM and igD since there is no switch after cdelta

Question 30

igM is produced since

Answer 30

C mu is the first after VDJ

Question 31

a cell that can make igM can also make

Answer 31

igD

Question 32

in a naive B cell the membrane ig include

Answer 32

igM and igD

Question 33

compared to memory cells, naive B cells have a lag time of ______ and a time of peak response of

Answer 33

4-7 days 7-10 days

Question 34

compared to naive B cells, memory B cells have a lag time of ______ and a time of peak response of ______

Answer 34

1-3 days 3-5 days

Question 35

in a memory B cell what igG predominates?

Answer 35

igG

Question 36

naive B cells have a _____ antibody affinity while memory B cells have a _____ antibody affinity

Answer 36

low;high

Question 37

compared to memory b cells, naive b cells life span is ______ lived

Answer 37

short (days to weeks) while memory is up to the life span of animal host

Question 38

The secondary response to antigen is drastically higher for what ig?

Answer 38

igG

Question 39

T-dependent antigens produce

Answer 39

memory B cells

Question 40

membrane ig of memory b cells

Answer 40

igM, IgG, igA or igE

Question 41

anatomical circulation of naive B cells is ________ and memory B cells is________

Answer 41

spleen, LN, corculation, circulation throughout the body

Question 42

all proteins are _______ while carbohydrates, lipids and nucleic acids are often not_______

Answer 42

immunogenic

Question 43

what are the requirements for immunogenicity?

Answer 43

1. foreignness 2. high molecular weight 3. chemical complexity 4. degradability

Question 44

the more _____ a substance, the ____ immunogenic

Answer 44

foreign more

Question 45

how can a molecule with lower molecular weight become immunogenic?

Answer 45

coupling it with a larger carrier compound

Question 46

T cells recognize antigens how?

Answer 46

only after they have been processed by APCs

Question 47

how do APCs degrade antigens ?

Answer 47

since APCs express major histocompatibility complex class I and II, they enzymatically degrade antigens into antigenic peptides (4-10 aa in length) which bind to MHC for presentation to T cells

Question 48

isotypic determinants

Answer 48

different epitotes help us determine ig isotype

Question 49

allotypic determinants

Answer 49

same ig antibody isotype from different strains

Question 50

idiotypic determinants

Answer 50

same ig isotypes but different CDRs

Question 51

strongest response is from what route of antigen administration?

Answer 51

subcantaneous

Question 52

adjuvants

Answer 52

substances that enhance immune response against the immunogen when mixed with an immunogen

Question 53

the only adjuvant allowed to be used in humans is

Answer 53

aluminum potassium sulfate.

Question 54

injection of rabbit igA against mouse would generate antibodies against?

Answer 54

rabbit j chain, rabbit alpha heavy chain

Question 55

how is BCR signalling shut down?

Answer 55

CD22 OR FcgammaRIIB which comatin ITIMS

Question 56

activation of SHP-1 would have what immediate effect downstream of BCR activation?

Answer 56

dephosphorylation of ITAMS

Question 57

how do B-10 B cells act as negative regulators ?

Answer 57

secrete il-10 which shuts down inflammatory responses by T cells and APCs