Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Immunology > Immunity mediated by B cells and antibodies > Flashcards

Immunity mediated by B cells and antibodies Flashcards

1
Q

B cell activation requires ___

A

2 signals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What 2 signals are required?

A
  1. Antigen binding B receptor
  2. Helper T Cell delivers 2nd Signal – CD40

Cytokines also help

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the Antigen Binding signal

A
  1. B cells become cross-activated when receptors are linked
  2. Clustering allows receptor ass. kinases to Phs. ITAMs
  3. Syk binds double P’d ITAMs, is activated
  4. Changes in gene expression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

3 B Cell components of Co-receptor complex

A

CR2
CD19
CD81

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does CR2 bind?

A

C3d

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the purpose of the coreceptor complex?

A

To lower the threshold of B cell activation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Four Activities Following B Cell Activation

A

Proliferation
Somatic Hypermutation (Affinity Maturation)
Isotype Switching
Dev. of Memory and Plasma cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What B cells are present in the Mantle Zone?

A

Naive Unactivated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What B cells are present in the Germinal Centers?

A

Active, Proliferating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What do B Cells need to enter the LN (via afferent lymphatic)

A

Actual Antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Antigen goes from the afferent lymphatic into the ______

A

Subcapsular Sinus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does antigen get from the subcapsular sinus into the Node?

A

Macrophage pickup using CR2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do Peyer’s Patches/Tonsils let in antigen?

A

Specialized epithelial cells for transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Steps of Naive B Cell Activation

A
  1. Naives look for their antigen on FDC
  2. Antigen Activated Bs go to Boundary region
  3. AA Bs present ant to effector T-fh cells - form pair
  4. Bound pairs migrate to medullary cords, EXPANSION
  5. Bound pairs migrate to Primary Follicle, 2dary EXPANSION
  6. Expansion of Primary Follicle generates Germinal Center
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Germinal centers are full of what cell?

What does this cell do?

A

Follicular Dendritic Cell

CR1 and CR2 on FDCs holds antigen in place for several months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is a follicular dendritic cell different than a DC?

A

Fibroblast lineage, Not from BM

No MHC II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How does somatic hypermutation work?

A

Activated B cell mutates V regions
Different versions of the B cell compete for binding to the antigen on the Folicular cell
No Binding = Death, Higher Affinity Bs bind, receive anti-apoptotics from helper T.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Two important signals a B gets from a T helper

A
  1. CD40 triggers isotype switching

2. Cytokines afterward influence what switching will occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

IFN-gamma drives what B cell type expression?

A

IgG2a, IgG3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

TGF-beta and IL-5 trigger what diff in B cells

A

IgA, IgG2b

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Il-4 triggers what kind of differentiation?

A

IgE, IgG1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Antigen selected centrocytes will tend to become plasma cells if exposed to _____ or memory cells if exposed to _______>.

A

Plasma – IL-10

Memory – IL-4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Mutation of CD40L will cause…

A

Hyper-IgM syndrome

Lack of Isotype Switching

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Inheritance of Hyper-IgM syndrome?

A

X linked

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is seen in the blood of a Hyper-IgM syndrome patient

A

No IgG, IgA

Increased IgM

26
Q

How do TI-1s activate B cells?

A

Via a non Ig receptor, for example using TLR4 to activate upon exposure to LPS

27
Q

How to TI-2s activate B cells

A

Chains of epitopes that cause extensive cross linking signaling of Ig on B cell surface

28
Q

What do TI-2s tend to target?

A

Polysaccharids, sometimes proteins

29
Q

Why is it important that TI-2s can act without help from T cells?

A

Ts recognize peptide fragments.

Polysachharide aren’t processed that way, so no CD4s

30
Q

T-dependent, TI-1, TI-2. Who is present in athymic people?

A

TI-1, TI-2

31
Q

T-dependent, TI-1, TI-2. Who does idotype switching?

A

Only T-dep

32
Q

T-dependent, TI-1, TI-2. who makes memory cells?

A

Only T dep

33
Q

T-dependent, TI-1, TI-2. Who works in infants?

A

Tdep and TI-1

34
Q

How do conjugate vaccines work?

A

Polysaccharide target is bound to a peptide toxoid
B cell binds antigen, toxoid is presented to Thelper
Activated B differentiates into plasma cell against polysac.

35
Q

Three bacteria targeted by Conjugate polysaccharide vaccines?

A

Haemophilius influenzae
Streptococcus pneumoniae
Neisseria meningitidis

36
Q

What is streptococcus pneumoniae?

Gram? Symptoms? Serotypes?

A

G+
Upper Resp. Inf, Otitis Media, Pneumonia
Over 90 serotypes

37
Q

Problems with using a vaccine against only the most common disease types?

A

Increases in prevalence of non-vaccine types

38
Q

Unique movement of IgA and IgG?

A

IgA – Across Epithelials into Mucosal Secretions

IgG – Across Endotheliams into Extravascular Space and across placenta

39
Q

What receptor mediates IgA travel across epithelial cells?

A

Polymeric Immunoglobulin Receptor

40
Q

What receptor mediates IgG travel across endothelial cell

A

Brambell Receptor (FcRB

41
Q

How does IgA get across epithelial cells?

A

Binding to poly-Ig rec. on the basolateral face
Endocytosis + Transcytosis
Receptor Cleaved
IgA bound to Mucus through Secretory Piece

42
Q

Poly-Ig receptor can transfer which two antibodies

A

IgA and IgM (but almost always does A)

43
Q

How big is A1 hinge region? A2?

A

26 aa

13 aa

44
Q

Role of secretory componeny in IgA dimer?

A

Wraps around J Chain – May help prevent protease activity

45
Q

IgA2 is most found…

A

In the digestive tract (esp. Ileum+Colon)

Shorter chain makes harder to cleave there

46
Q

How does IgG get across endothelial cells?

A

Binding to FcRB, transcytosis

Mostly active transport

47
Q

At birth, what antibodies does an infant have?

Which come along later?

A

Maternal IgG and Fetal IgM

Fetal IgA and IgG

48
Q

Name three effector functions of antibodies.

A

Neutralization
Opsonization
Complement Activation

49
Q

Who expresses Fc-gamma receptors?

A

Neut, Mac, B Cells, FDCs, NKs

50
Q

Purpose of Fc-gamma receptors?

A

Opsonization and Antibody-dependent cell-mediated cytotoxicity

51
Q

Purpose of Fc-epsilon receptors? Who expresses them?

A

Important in allergic reactions

Expressed on Mast Cells and Basophils

52
Q

FcR1 is on _____ and has a high affinity for ___

Describe its action.

A

Mac and Neut. IgG1 and IgG3
FcR1 binds the lower hinge/CH2 of Ig, Ig binds antigen
More efficient phagocytosis

53
Q

Which Fc has the strongest relative binding strength to IgG1?

A

Fc-gamma R1 (CD64)

54
Q

Which Fc-gamma receptors are inhibitory

A

RIIIB2, RIIIB1

CD32

55
Q

How does antibody dependent cell mediated cytotoxicity work?

A

Antibody binds target
Fc receptors of NK cells recognize Ab
Crosslinked Fc receptors signal NK cell to kill the target
Apoptosis

56
Q

Describe the relationship of IgE and Mast Cells

A

IgE binds onto Fc-gammaR1 on mast cells

On second exposure, antigen binding to bound antibodies will trigger degranulation

57
Q

IgG3 is unique for…

A

Long Hinge
Large Heavy Chain + many disulfide bonds
Very susceptible to clevage, so short half-life
Great ability to activate complement

58
Q

What is IgG4 good at?

A

Allergen Response

59
Q

How long do untriggered naive B cells live?

60
Q

Short lived plasma cells in the medulla generate….

A

IgM for approx. 5 days

Forms initial response to infection

61
Q

What happens in secondary response if Naive B binds to a path coated in antibody?

A

Negative signal is given to naive B

Activation prevented

62
Q

What happens in secondary response if Memory B cell binds a pathogen coated in Ab?

A

Memory B is activated
Becomes a plasma cell
Produces high-affinity IgG, A, and E

Immunology (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions