Antibody Structure (complete) Flashcards

1
Q

Define H Chain

A

AKA: Heavy chain
MW: 50,000
5 types: gamma, alpha, mu, epsilon, delta (corresponds with each Ab)

  • Each Ab has at least 2 H chains
  • Each H chain has 1 variable domain [V(H)]
  • Also 3-4 constant domains [C(H1-4)]
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2
Q

Define L Chain

A

AKA: Light chain
MW: 25,000

  • Each Ab has at least 2 L chains
  • Each L chain has 1 variable domain [V(L)]
  • Also 1 constant domain [C(L)]
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3
Q

Define kappa and lambda chains

A

2 kinds of L chain

Each cell that makes Ab has a choice between the two, but only uses one kind

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4
Q

Define hinge region

A

Allows for flexibility

When bound to antigen, constant part of Ab can change conformation

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5
Q

Define Fab, F(ab2), Fc

A

Fab: S–S bonds between H chains fully reduced

F(ab2): 2 Fabs still joined by S–S bond

Fc: non-antigen binding region of Ab — makes Ab participate in the complement system

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6
Q

Define complementarity-determining regions (hypervariable regions)

A

3 regions with most of the variability — AA variability

This is the area unique to the Ab! It binds the Ag!

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7
Q

Define variable (V) and constant (C) domains

A

V: at N-terminal end of Ab, differences in AA sequences between Abs of different specificities

C: region (almost) identical on Abs, made of 1 (L chain) to 4 (epsilon and mu) compact, structurally similar domains called C domains

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8
Q

Define V(L) and C(L)

A

V: variable domain of L chain

C: constant domain of L chain

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9
Q

Define V(H) and C(H)

A

V: variable domain of H chain

C: constant domain of H chain

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10
Q

Draw an electrophoretic separation of human serum. Identify the albumin, alpha(1), alpha(2), beta and gamma peaks.

A

GO DRAW IT ! or at least look it uppppp :D

Serum put into electrophoresis and makes this graph — Ab activity seen in the gamma region

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11
Q

Name the 5 antibody classes

A

1) IgG
2) IgE
3) IgD
4) IgA
5) IgM

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12
Q

What is in the structure of IgG?

A
  • 2 L chains

- 2 gamma (H) chains

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13
Q

What is in the structure of IgE?

A
  • 2 L chains

- 2 epsilon (H) chains

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14
Q

What is in the structure of IgD?

A
  • 2 L chains

- 2 delta (H) chains

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15
Q

What is in the structure of IgA?

A
  • 4 L chains
  • 4 alpha (H) chains
  • 1 joining (J) chain
  • 1 secretory (S) component
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16
Q

What is in the structure of IgM?

A
  • 10 L chains
  • 10 mu (H) chains
  • 1 joining (J) chain
17
Q

Draw a diagram of the structure of IgG. —- Label heavy and light chains, Fc and Fab parts, J chains if any, Ab combining sties, main interchain disulfide bonds, secretory components

A

GO DRAW IT

18
Q

Draw a diagram of the structure of IgE. —- Label heavy and light chains, Fc and Fab parts, J chains if any, Ab combining sties, main interchain disulfide bonds, secretory components

A

GO DRAW IT

19
Q

Draw a diagram of the structure of IgD. —- Label heavy and light chains, Fc and Fab parts, J chains if any, Ab combining sties, main interchain disulfide bonds, secretory components

A

GO DRAW IT

20
Q

Draw a diagram of the structure of IgA. —- Label heavy and light chains, Fc and Fab parts, J chains if any, Ab combining sties, main interchain disulfide bonds, secretory components

A

GO DRAW IT

21
Q

Draw a diagram of the structure of IgM. —- Label heavy and light chains, Fc and Fab parts, J chains if any, Ab combining sties, main interchain disulfide bonds, secretory components

A

GO DRAW IT

22
Q

Arrange IgG, IgM, and IgA in terms of molecular size..

A

IgM > IgA > IgG

900K > 400K > 150K

23
Q

What are the approximate normal concentrations in serum of IgG, IgM, and IgA.

A

IgG: 1000 mg/dL
IgM: 100mg/dL
IgA: 200mg/dL

dL = 100mL

24
Q

Describe the structure of Ab combining sites.

A

Where the Ab binds to the antigen

Made up of V domains of both H and L chains [aka V(H) and V(L)]

25
Explain why complementarity-determining regions are also called hypervariable regions.
- 3 hypervariable regions on the variable domain of L and H chains - these have more AA variability - AAs in hypervariable regions comprise the actual antigen-binding site
26
Give an example of a subclass
Immunoglobulins are divided into subclasses b/c of slight differences in AA sequence on C(H) IgG1, IgG2, IgG3, IgG4 ... IgA1, IgA2... etc
27
Give an example of an allotype
Minor allelic differences in immunoglobulin sequences between individuals Determined by allotypes of parents
28
Give an example of an idiotype
Unique combining region Made up of CDR AAs of its L and H chain that each Ab has
29
What is an anti-idiotype?
Abs made that recognize the unique sequence of that combining site