B cells

Question 1

what is key to clonal selection

Answer 1

each lymphocyte has receptors to only a single antigen

Question 2

know clonal selection maps

Answer 2

see notes

Question 3

main B cell funct.

Answer 3

make antibodies to mark things for detruction

Question 4

what are steps to make an antibody

Answer 4

1. mature B cell bind with antigen
2. makes plasma cells
3. creates antibodies to that path.

Question 5

what is basic structure of antibody

Answer 5

1 heavy chain and 2 light chains
variable region (Fab) and constant region (Fc)

Question 6

4 functions of antibodies

Answer 6

1. neutralization of toxins/bact
2. opsinization
3. activation of complement cascade
4. help activate special cells

Question 7

how does anti-body neutralize toxin/virus

Answer 7

binds to it so it cannot bind to cell receptor and enter the cell

Question 8

how does antibody opsinize

Answer 8

Fab binds to bacteria and Fc binds to phagocytic cell and leads to phag of bact.

Question 9

how does antibody activate complement cascade

Answer 9

classical pathway - C3 activation

Question 10

what are antibody isotypes

Answer 10

different sublasses of anti bodies that have diff. functions and circulate in different areas

Question 11

what is location and function of IgG

Answer 11

• small and all tissues

- opsinization and complement activation (C1)

Question 12

what is location and function of IgM

Answer 12

• pentameric structure that is large and can’t leave blood

- binds strongly as first line and can also activate complement

Question 13

what is location and function of IgA

Answer 13

• in secretions esp resp and intestinal tracts

- poor opsonin and weak complement activator

Question 14

what is location and function of IgE

Answer 14

• trace amount in serum, most in mast cells under skin

- binding causes mast cells to degranulate leading to sneeze cough - involved in allergic rxns

Question 15

how do B cells recognize antigen

Answer 15

with same imbedded immunoglobin that will become and antibody

Question 16

what are 2 things B cell dev. must acheive

Answer 16

1. large repetoire of antibodies

2. antibodies that can function in different ways (ISOtypes)

Question 17

how does B cell gen diversity?

Answer 17

through recombining V,D,J in somatic recombination

Question 18

what is light chain recombination steps

Answer 18

1. germline DNA
2. recombination
3. VJ joined DNA

Question 19

what is heavy chain recombination steps

Answer 19

1. germlineDNA
2. recombination
3. DJ joined DNA
4. recombination
5. VDJ joined DNA

Question 20

how does recombination control lymphocyte dev (2)

Answer 20

1. allows progression to next stage

2. prevent further rearrangement allowing single specificity for each cell

Question 21

where are 2 checkpoints in dev.

Answer 21

after heavy and light chain rearrangments

Question 22

what happens if no receptor made?

Answer 22

apoptosis

Question 23

where does rearrangment occur

Answer 23

bone marrow

Question 24

what is product of rearrangment

Answer 24

immature B cell in bone marrow with IgM on surface

Question 25

what is key life event of B cell

Answer 25

expression of IgM on surface

Question 26

what is tolerance

Answer 26

only those B-cells that do not recognize self antigen are allowed to leave bone marrow

Question 27

where does B-cell go after marrow

Answer 27

secondary lymphoid tissues

Question 28

how does Bcell know where to go

Answer 28

chemokines

Question 29

where does B cell go in lymph node

Answer 29

1. to T cell area to look for antigen | 2. if none move to B cell area in cortex

Question 30

3 requirements for B cell activation

Answer 30

1. cross-linking of surface imunoglobulin by specific antigen 2. association of Bcell receptor with B cell co-receptor 3. additional signal from helper T cell

Question 31

what is T-cell help

Answer 31

1. B cell links with T cell with same antigen spec. 2. linkage causes T cell to release cytokines that activate B cell 3. B cell become plasma cell

Question 32

what happens when B cell meets correct T cell in node

Answer 32

1. cognate pair travel to medularry cords 2. undergo clonal expansion 3. cause primary focus

Question 33

what is primary focus

Answer 33

rapid early diff of B cells without T cells to create IgM as initial attack

Question 34

what is secondary focus

Answer 34

movement of activated B cells out to form a germinal center

Question 35

what is in germinal center (3)

Answer 35

1. activated B cells 2. T cells 3. antigen

Question 36

what occurs in the germinal center

Answer 36

rapid B cell prolif. leads to 1. somatic hypermutation 2. affinity maturation

Question 37

what is affinity maturation

Answer 37

finds B cells that have strong affinity for antigen and brought to T cell for extra reproduciton

Question 38

where does isotype switching occur

Answer 38

in the germinal center

Question 39

what is isotype switching

Answer 39

original expression of IgM is changed to another type

Question 40

how does isotype switching occur

Answer 40

due to recombination within the cluster of C genes

Question 41

what are outcomes of B cells in germinal center (2)

Answer 41

1. become plasma cell via IL-10 | 2. memory cell via IL-4

Question 42

how to identify and lymphocytic leukemia

Answer 42

will all have the same Ig receptor on surface

Question 43

how to identify myleloma (plasma cell)

Answer 43

will produce tones of same antibody

Question 44

what antibodies are in the brain and a fetus

Answer 44

brain - none | fetus - IgG

Question 45

what does IgA do

Answer 45

protects mucosal surface

Question 46

what is IgA mechanism

Answer 46

1. released from basement membrane and when bound is phagocytosed into cell and excreted into the lumen 2. once in lumen it can help bind bacteria etc. in tract to can't reporoduce and poo it out

Question 47

what is ADCC

Answer 47

antibody dep. cytotoxicity - opsinize so binds with NK cells

Question 48

how does C3b react with RBCs

Answer 48

1. bound C3b binds with CR1 receptor on RBC | 2. RBC carries it around until meets macrophage to take it off

Question 49

how does allergy happen

Answer 49

mast cell response binds to non-threatening antigens via IgE causing reaction

Question 50

what is anaphylaxis

Answer 50

make IgE to protein antigens such as peanuts and mast cell becimes coated 2. future contact leads to massive degranulation

Question 51

what are autoantibodies

Answer 51

antibodies that recognize self - loss of tolerance

Question 52

see conclusion slides

Answer 52

it will be helpful