B cell

Question 1

B cell negative selection occurs

Answer 1

bone marrow

Question 2

B cell precursor rearranges its ig genes

Answer 2

in the bone marrow stromal cell

Question 3

Immature B cell bound to self cell-surface is…

Answer 3

removed from the repertoire

Question 4

Two ways to initiate B cell activation and humoral response

Answer 4

1) thymus depend

2) thymus indepedent tho not as efficent

Question 5

which T cell activates the B cell

Answer 5

CD4 Helpter T cell

Question 6

First signal

Answer 6

delivered by antigen via BCR

Question 7

Second signal delivered by

Answer 7

1) thymus dependent > helper T cell

2) extensive crosslinking of surface igM
inefficent method of activation

thymus independent

Question 8

T cells can only recognize small…presented in the MHC pocket of the antigen presenting cell

Answer 8

peptide

Question 9

MHC II is loaded from material captured in the…

Answer 9

phaglysosome

Question 10

The antigen recognized by BCR does NOT have to be the ……it presents to CD4 helper T cell

Answer 10

doesn’t have to be the same antigen recognized, can present something different

Question 11

B cell captures molecular complexes/pathogen into its….via its…..

Answer 11

B cells use their BCR to capture antigen into their phagolysosome

Question 12

What does B cell use to capture its antigen

Answer 12

BCR

Question 13

BCR can recognize the external viral coat antigen but after digestion, the ……is presented to the T cell

Answer 13

internal viral antigen

hence forth the antigen recognized by B cell isn’t necessairly the same antigen it presents to CD4 t cell’

Question 14

After B cell presents the antigen peptide to T helper cell, the T helper cell…..

Answer 14

releases cytokines to active the B cell, and the activated B cell PRODUCES AB against the viral coat protein

Question 15

BCR can recognize……and…..unlike T cells which only recognize….

Answer 15

NON-peptides and peptides

Peptides for T cells only

Question 16

epitope

Answer 16

the part of an antigen molecule to which an antibody attaches itself.

Question 17

Read

Answer 17

Although the epitope recognized by the armed helper T cell must therefore be linked to that recognized by the B cell, the two cells need not recognize identical epitopes. Indeed, we saw in Chapter 5 that T cells can recognize internal peptides that are quite distinct from the surface epitopes on the same protein recognized by B cells. For more complex natural antigens, such as viruses, the T cell and the B cell might not even recognize the same protein. It is, however, crucial that the peptide recognized by the T cell be a physical part of the antigen recognized by the B cell, which can thus produce the appropriate peptide after internalization of the antigen bound to its B-cell receptors.

Question 18

TCR and BCR do not have to……..

Answer 18

B cell and its helper T cell (which was activated early by apc cell) don’t have to recognize the same epitope

Question 19

BCR captures a molecule by its polysacchride component but after digestion the…….component of the ingested is loaded onto the B cell’s ……and presented to CD4 T cell

Answer 19

PEPTIDE COMPONENT

MHC II

Question 20

antigen binding portion of antibody

Answer 20

Fab

Question 21

non antigen binding portion of antibody

Answer 21

Fc

Question 22

Why is the BCR can also recognize non-peptides and that T cells recognize peptides, in that they need not recognize the exact thing?

Answer 22

For pathogens with non-protein coat

Basically to develop a WIDE VARIETY of pathogens and toxin

Question 23

signal two invovles……

Answer 23

CD4 ligand on T helper cell, and CD4 ReCEPTOR on B cell

Question 24

LFA-1 of T cell also helps with T / B cell interaction

Answer 24

True

Question 25

T helper cells bound to b cells secrete

Answer 25

IL-4 into the space b/w the two cells

Question 26

Somatic hypermutation

Answer 26

B cell activation leads to mutations in the antigen binding regios of ig

Question 27

Rapidly proliferating cells are found in the….

Answer 27

germinal centers in secondary lymphoids

Question 28

Only B cells able to present antigent T cell are …..

Answer 28

stimulated to survive

Question 29

The ….the ab affinity the…..likelihood that B cell will outcompete other…..B cells for T cell help in surviving

Answer 29

HIGHER…..HIGHER….lower

Question 30

Where does somatic hyper mutation takes place?

Answer 30

Lymph node, b cell follicle area

Question 31

Where do immature B cells mature and and activate?

Answer 31

lymph node

Question 32

B cell and T cell interact where in the lymph node

Answer 32

paracortex

Question 33

Somatic hypermutation leads to changes in

Answer 33

BCR affinities

Question 34

What is the advantage of somatic hypermutation?

Answer 34

increase antibody affinity due to selective survival of B cell expressing higher affinity

Question 35

B cells ALL start out as ….. expressers but after actviation are stimulated to make…..,…..,or……

Answer 35

start out IgM

later activation

IgG or IgA or IgE

Question 36

What’s the point in having isotope switching and somatic hypermutation?

Answer 36

1) somatic hypermutation is for variability in the ANTIGEN BINDING REGIONS of the immunoglobulin

the higher affinity of the antibody the higher likely hood the higher the chance that the B cell will outcompete other lower affinity B cells to T cell to survivie

2) isotope switching is in the constant region, and whatever region comes after the variable region, the immunoglobulin is named after that

by default without isotope switiching all antibodies will be IgM

All of this is the increase the DIVERSITY

may antigen needs G constant region and a subclass of G by hypermutatin the antigen binding regions of IgG

once the B cell has figured which isotype and subtype it will secrete more