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Immunology -- Jones > Exam 1 -- Ch. 3 (B-cells and Antibodies--adaptive system) > Flashcards

Exam 1 -- Ch. 3 (B-cells and Antibodies--adaptive system) Flashcards

1
Q

What is the component of the Ag (antigen) that the Ab (antibody) interacts with? What part of the Ab is there?

A

epitope, which is the antigenic determinant

variable region of Ab binds to epitope

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2
Q

What are molecules too small to cause an immune response, but combined with a carrier molecule a response is generated?

A

Haptens

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3
Q

What is an example of a hapten?

A

penicillin

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4
Q

What can anitbodies also be called?

A

immunoglobulins

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5
Q

What are proteins that are produced in response to an Ag?

A

antibodies, which are highly specific

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6
Q

What is the part of the anitbody called in a serum fraction?

A

gamma globulin

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7
Q

What is the structure of an antibody?

A

Four polypeptides

  • two heavy chains (identical)
  • two light chains (identical)

Constant Region
Variable Region

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8
Q

What joins the chains of the anitbody?

A

disulfide bridges

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9
Q

What is the antigen binding portion of the antibody called?

A

Fab

Antigen Binding portion

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10
Q

What is the stem part of the antibody called?

A

Fc region

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11
Q

Describe the constant region and the variable region of the antibody.

A

Constant regions– stay the same (stem)

Variable regions– changes (antigen-binding portion; “Fab”)

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12
Q

What are the five classes/isotypes of immunoglobulins? What are they based on?

A

Based on constant region–heavy chain of Ab; and they play diff roles.
“GAMED”
IgG, IgA, IgM, IgE, IgD

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13
Q

What are the four subclasses of IgG?

A

IgG1, IgG2, IgG3, IgG4

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14
Q

What is the most dominant Ab’s in serum (blood)?

A

IgG

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15
Q

What Ab can cross blood vessels?

A

IgG

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16
Q

What Ab can cross the placenta?

A

IgG

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17
Q

What Ab activates the complement system? Specifically which one?

A

IgG, and IgM

the Classical pathway

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18
Q

What does IgG enhance? What does it help eliminate?

A

enhances phagocytosis

helps eliminate bacteria, viruses, and bacterial toxins

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19
Q

What is the most abundant Ab in the body?

A

IgA

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20
Q

Where do we find IgA?

A
  • ass. with mucous membranes

- found in mucus, tears, saliva, as “secretory IgA”

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21
Q

What Ab is associated with mucous membranes?

A

IgA

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22
Q

We know IgA is found in mucous membranes, but how is it protective there?

A

prevent viral and bacterial attachment to mucosal lining = neutralization

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23
Q

What kind of structure is IgA and how is that beneficial?

A

dimer

- allows transport into GI tract

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24
Q

What Ab can cluster pathogens together? And what is that called?

A

IgA and IgM; agglutination

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25
Q

What Ab is found in breast milk?

A

IgA; and can coat baby’s GI tract

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26
Q

What structure is IgM?

A

pentamer (5)

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27
Q

Which Ab is the predominant Ab against RBC antigens?

A

IgM

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28
Q

Which is the first type of Ab to appear in response to “new” antigen?

A

IgM; is an excellent activator of compliment system

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29
Q

T/F. IgM can cross vessels easily.

A

False– IgM cannot cross vessels easily, like the placenta

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30
Q

Which Ab is associated with allergies?

A

IgE

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31
Q

What does the IgE antibody do?

A
  • bind to mast cells and basophils
  • release histamine
  • attracts phagocytes
  • effective against parasitic worms
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32
Q

Which Ab is effective against parasitic worms?

A

IgE

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33
Q

What part of the Ab of IgE do mast cells bind?

A

Fc (stem)

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34
Q

Upon first exposure to antigen some make IgE, but what happens on the second exposure?

A

Ag binds IgE, which is on Mast cells, and causes degranulation

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35
Q

What are two possible results when the IgE Ab is involved in a response?

A
  1. Small local impact

2. Large systemic impact

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36
Q

What does a small local impact entail from involvement of IgE?

A
  • increase capillary permeability

- usually a local effect (runny nose)

37
Q

What does a Large systemic impact involve for an IgE response?

A
  • massive degranulation throughout body–> can decrease blood volume drastically to point of a heart attack
  • contraction of smooth muscle of respiratory tract (difficult breathing –> suffocation)
38
Q

Which Ab can cross placenta, an OK complement fixer, good opsonizer, and helps NK cell kill?

A

IgG

39
Q

Which Ab if first Ab made, a great compliment fixer, and a good opsonizer?

A

IgM

40
Q

Which Ab causes allergies, defends against parasites, and causes anaphylactic shock?

A

IgE

41
Q

Which Ab is in mucosal secretions, is resistant to stomach acid, protects mucosal surfaces, and is secreted in milk?

A

IgA

42
Q

Where do B cells come from?

A

Hematopoietic stem cells

43
Q

What are B cells?

A

WBCs (from bone marrow) that make antibodies

44
Q

How many different kinds of B cells are there? How many are made a day? How many are in the blood?

A

100 million kinds of B cells

1 billion new ones produced a day

3 billion in blood

45
Q

Do B-cells have specific or general Ag receptors for one Ag?

A

specific

46
Q

What are the receptors that are on B cells?

A

Ab’s, specifically IgM or IgD

47
Q

How is a B cell activated?

A

Ag binds to Ab on the B-cell and activates it

48
Q

The Ag will select what B-cells proliferates, what is that called?

A

Clonal selection (2 fates)

49
Q

What are the two fates of B-cell once it is activated?

A
  1. plasma cells produce Ab 2000/sec

2. Memory cells last for decades

50
Q

Once the Ag/Ab complex is formed what occurs?

A

tags foreign cells/molecules for destruction

51
Q

What are the 5 protective mechanisms of binding antibodies to antigens?

A
  1. agglutination
  2. opsonization
  3. neutralization
  4. antibody dependent cell mediated cytotoxicity
  5. complement activation
52
Q

What do theses 5 protective mechanisms consists of?

  1. agglutination
  2. opsonization
  3. neutralization
  4. antibody dependent cell mediated cytotoxicity
  5. complement activation
A
  1. clumping Ag
  2. enhances phagocytosis
  3. block viruses and toxins
  4. tag worm with Ab
  5. lysis and inflammation
53
Q

What is the antibody titer?

A

measures the level of Ab in blood, telling us the intensity of response

54
Q

When it comes to Ab memory, what Ab is most involved in the primary response? What about the secondary response?

A

Primary response = IgM

Secondary response = IgG

55
Q

What is the secondary Ab response important for? Which Ab is involved?

A

IgG, important for a faster response

56
Q

Describe the Modular Design of the Heavy chain part of the Ab.

A

there are multiple copies of four gene segments that code the antibody’s heavy chains
(V, D, J, C)

57
Q

What do the V, D, J, and C stand for on the heavy chains?

A

variable
diversity
junctional
constant

58
Q

The Fc region is a string of gene segments where are……?

A

(Fc is constant part of heavy chains)

Cm, Cd, Dg, Ce, Ca

59
Q

Describe the Modular Design of the light chain part of the Ab.

A

there are multiple copies of 3 gene segments that code that antibody’s light chain (V, J, C)

(NO D region!!)

60
Q

What are the light chains availability for its constant region?

A

L or K

61
Q

What is junctional diversity?

A

how we “glue” the various gene segments together; an imperfect process that includes deletion and addition of nucleotides(DNA bases) b/w the gene segments

62
Q

What is the Combinatorial Process?

A

combination of heavy and light chains (the two Variable segments light up and give MORE specifity)

63
Q

Overall, what are the three things that give Antibody Diversity?

A
  1. Modular Design
  2. Junctional Diversity
  3. Combinatorial Process
64
Q

On a given B cell are all the BCR’s the same?

A

YESSSSSS

- recall IgM and IgD serve as the BCR’s

65
Q

What are B cells called that have never encountered their cognate antigen?

A

“naive” or “virgin” B cells

66
Q

What are B cells called that have been activated?

A

“experienced” B cells

67
Q

Describe the pathway of the B-cell signaling its nucleus. (~ 4 steps)

A
  1. B cell encounters its “cognate antigen”
  2. BCR binds the epitope
  3. Mult. Ag or sights on Ag bind to BCRs
  4. BCRs cluster or “crosslink”
68
Q

When the BCRs cluster or “crosslink” what occurs?

A

the Ig-alpha and Ig-beta interact with enzymes inside the cell ——> when clustered together the signal may be strong enough to activate the nucleus

69
Q

What are the Ig-alpha and Ig-beta portions of the BCRs?

A

They are NOT part of the Ab, but are ass. with the BCRs and are the integral membrane proteins

70
Q

How many signals do B-cells need to be “activated”?

A

Two!

  1. B cell receptors binding Ag and then cluster
  2. Co-stimulatory signal enhances signaling
71
Q

What are the two sources of B-cell Co-Stimulation?

A
  1. T-cell dependent co-stimulation (BETTER)

2. T-cell independent co-stimulation

72
Q

Which Co-stimulation of the B-cell is it when some antigens have repeating patterns and will heavily cluster the BCRs and additional receptors bind the antigen or complement, all independent of Tcells?

A

T-cel independent co-stimulation

73
Q

How does the T-cell Dependent Co-stimulation work? (~5 steps)

A
  1. B- cell encounters its cognate antigen
  2. B-cell endocytosis its cognate antigen
  3. B-cell presents peptide fragments on MHC II on its surface
  4. T cell meets its cognate antigen (MHC II peptide on B-cell)
  5. T cell’s CD40 binds the B-cell’s CD40L

***DUAL CONFIRMATION

74
Q

How does the T-cell Independent Co-stimulation work?

A
  1. B-cell encounter its cognate antigen that has repeating sequence/pattern
  2. BCRs cluster (1st signal)
  3. Co-stimulatory receptor (TLR or complement receptor = type of PRP, a bacterial component)
  4. no T-cell needed to stimulate response
75
Q

What is the Un-natural B-cell co-stimulation involve?

A
  1. Anitgen (mitogen) binds to B cell molecules that are not BCRs
  2. the non BCR molecules cluster
  3. BCRs cluster with non BCR molecules
  4. signal NOT dependent on cognate antigen for a given B cell
76
Q

Why do some pathogens use the un-natural B-cell co-stimulation way? What does it result in?

A

rely on this to confuse the immune system and skip the specificity

results in polyclonal activation of B cells

77
Q

After activation and proliferation, what do B cells go through next?

A

maturation process

78
Q

What are the the three processes for the B-cell maturation process?

A
  1. Somatic Hypermutation
  2. Career Decision
  3. Class Switching
79
Q

What does the Somatic Hypermutation part of B-cell mutation involve?

A
  • BCR genes undergo mutation and selection

- creating a greater affinity of the BCR for its cognate antigen

80
Q

Ont he B cell chromosomes (regions containing V, D, and J gene segments) undergo one mutated base pair per __________ per DNA replication cycle.

A

1000 bases per DNA replication cycle

  • very restricted to these chromosomes and these regions
  • fine tunes antigen specificity of BCR and antibodies
81
Q

What is changed during the Somatic Hypermutation part of B-cell maturation process?

A

changes the antigen binding region of the antibody —> therefore may INCREASE or DECREASE affinity of Ab for its cognate antigen, or affinity remains unchanged

82
Q

What are the three possibilities during Somatic Hypermutation of the B-cell when the antigen bonding region of the Ab is changed?

A
  1. Increase affinity of Ab for Ag
  2. Decreases the affinity of the Ab for its Ag
  3. affinity of Ab for Ag is unchanged
83
Q

In order for B-cells to continue proliferating they need ongoing signal, how does this affect them?

A
  • B-cells mutating toward higher affinity BCRs are STIMULATED more easily
  • B-cells mutating toward lesser affinity BCRs are NOT stimulated and cease to multiply
84
Q

What are the Two Career Choices that B-cells have during the maturation process?

A
  1. Plasma Cell

2. Memory cell

85
Q

What do Plasma cells do? Where to they usually go? How long do they live?

A
  • create Ab’s, up to 2000 per second
  • back to spleen or bone marrow
  • few days
86
Q

What do Memory cells do?

A
  • wait for next time

- provide faster secondary response

87
Q

How do we make different classes of antibodies? How do we class switch them?

A
  • Make classes: “GAMED”
  • determined by Fc (constant) region of heavy chains
  • B-cells cut and paste diff constant regions
88
Q

What class of the constant region of an Ab is most common?

A

IgM, b/c that is first in line on the constant region

89
Q

What are the overall goals of B-cells and Ab?

A
  • create diversity in Ab structure
  • rapid response to make fore B-cells to combat specific Ag
  • rapid ability to create Ab’s specific to Ag
  • fine tune Abs
  • create long-lasting memory of Ag’s

Immunology -- Jones (14 decks)

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