Lecture 9 - B cell response/antibodies

Question 1

Humoral immunity

Answer 1

antibody-mediated

Question 2

why does the plasma cells have more space

Answer 2

needs for endoplasmic reticulum and antibody synthesis

Question 3

If immature B cells do not find an antigen they

Answer 3

leave the bone marrow

Question 4

if BCR binds to self-antigen they

Answer 4

are eliminated via apoptosis or undergo receptor editing

Question 5

If a B cell is still reactive to self antigens following receptor editing they

Answer 5

undergo apoptosis

Question 6

Central tolerance of B cells refers to

Answer 6

The double-positive system before leaving the bone marrow

Question 7

Transitional B cells are

Answer 7

B cells that have exited the bone marrow into circulation

Question 8

Peripheral tolerance of B cells refers to

Answer 8

Single positive system of B cells maturation in the spleen

Question 9

Transitional B cells with no strong self reaction

Answer 9

mature

Question 10

what is the final stage of B cell maturation

Answer 10

upregulation of surface IgD

Question 11

summarize the stages of B cell development

Answer 11

1 - stem cell in bone marrow
2 - pre B cell in lymphoid organs
3 - immature B cell obtain membrane IgM and IgD
4 - mature B cell in secondary organs obtain antigen
5 - plasma cells secrete immunoglobulins

Question 12

T/F: other species have peyer’s patches but they are not the primary organ like in pigs

Answer 12

True

Question 13

Fc receptors bind to

Answer 13

the B cell membrane

Question 14

complement receptors do what

Answer 14

regulate

Question 15

cytokine receptors do what

Answer 15

co-stimulate and regulate

Question 16

BCRs consist of

Answer 16

immunoglobin domains

Question 17

what domain of the BCR is the antigen-binding site

Answer 17

light chains

Question 18

what are the signal transduction components of BCR

Answer 18

CD79 alpha and beta

Question 19

how are BCRs and TCRs similar

Answer 19

antigen-specific
respond to epitomes presented in the linear form

Question 20

How are BCRs different from TCRs

Answer 20

recognize free-floating native (3D) antigen, giving them more binding variety

Question 21

Summarize activation of helper T cells via B cells

Answer 21

1 - antigen binds to BCR and is ingested
2 - antigen is bound to MHC II
3 - MHC II is presented on the membrane to TCRs

Question 22

where are antigens presented to B cells

Answer 22

lymph nodes

Question 23

How are B cells activated

Answer 23

dendritic cells present linear antigens or unprocessed native (3D) bind

Question 24

summarize T cell-independent B cell activation

Answer 24

1 -polyvalent antigen binds to multiple BCR
2 - production of IgM (low affinity)

Question 25

Summarize cross-links

Answer 25

1 - native antigen endocytosed 2 - expressed by B cell MHC II (exposure tp PAMPs and complements upregulate stimulatory molecules) 3 - processed epitopes to CD4+ T cells 4 - TCR binding induces CD154 expression 5a - CD154 binds to CD40 on B cell promoting immunoglobulin synthesis and proliferation 5b - CD40 promotes CD86 expression on B cells 6 - CD86 binds CD28 on T cell 7 - IL4 cytokine production

Question 26

what does IL4 cytokine production give as an effect of cross-links

Answer 26

B cells differentiate

Question 27

what mediates class switching of IgM to another immunoglobin

Answer 27

cytokines

Question 28

T/F: B cell immunoglobins are controlled by T cells

Answer 28

True

Question 29

what determines an immunoglobins isotype

Answer 29

1/5 heavy chains

Question 30

Immunoglobin structure

Answer 30

2 heavy and 2 light chains

Question 31

What immunoglobins lack a hinge region? what do they have instead?

Answer 31

IgM and IgE; extra heavy chain

Question 32

IgM

Answer 32

immature b cells and antigen-specific BCR primary immune response can activate complement

Question 33

IgG

Answer 33

B cells in secondary response can activate complement

Question 34

IgA

Answer 34

mucosal surfaces, secreted by MALT secretory component CANNOT activate complement

Question 35

IgD

Answer 35

immature B cells; function unclear

Question 36

IgE

Answer 36

immunity to parasitic worms and allergies forms cross-links CANNOT activate complement

Question 37

Fc fragments mediate what functions

Answer 37

- complement activation - opsonization - cellular activation

Question 38

What are the 5 biological functions of antibodies

Answer 38

1. neutralization of microbial actions/toxins 2. opsonization 3. NK kills antibody-bound cells 4. lysis of abnormal cells 5. IgE activation of mast/eosinophils

Question 39

what part of the antibody is variable

Answer 39

antigen-binding site

Question 40

VDJ

Answer 40

heavy chain

Question 41

VJ

Answer 41

light chain

Question 42

What recombination occurs in terminal differentiation

Answer 42

light chain rearrangement

Question 43

Summarize affinity maturation

Answer 43

- B cells activate - mutation initiated by AID, turning cytidine to uridine - error-prone DNA polymerase fixes uridine presence introducing further mutations - changes arise in variable regions - B cell with highest affinity to antigen differentiates to plasma cell

Question 44

What does affinity maturation contribute to

Answer 44

improved antigen binding abilities of antibodies

Question 45

What is isotype switching

Answer 45

activated B cells switch from producing IgM/IgD to IgG/IgA/IgE

Question 46

Thelper 1 cell induce what isotype

Answer 46

IgG

Question 47

Thelper 2 cell induce what isotype

Answer 47

IgE

Question 48

Treg cells induce what isotype

Answer 48

IgG

Question 49

what does isotype switching improve

Answer 49

antibody function in the Fc region

Question 50

B1 cell characteristics

Answer 50

less common spontaneously produce IgM/"natural antibodies" target lipids/carbohydrates

Question 51

The binding of Fc antibody portions to their receptors can trigger what sorts of actions

Answer 51

1. phagocytosis/killing 2. degranulation 3. downregulate inflammation

Question 52

T/F: antibodies are found bound to their Fc receptors

Answer 52

False