Brainscape's Knowledge GenomeTM

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


See full index

BIOC2301 > Proteins: Antibody Structure and Tools > Flashcards

Proteins: Antibody Structure and Tools Flashcards

1
Q

What is the Ig superfamily domain?

A

Structurally stable, autonomously folding unit they has a conserved secondary and tertiary structure, not only found in antibodies.

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

What is the structure of antibodies?

A

Dimers of dimers with heavy and light chains held together by disulphide bonds which have variable and constant regions with huge diversity.

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

What produces antibody diversity?

A

Combinational diversity, junctional diversity, hyper mutation.

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

How many classes of Ig are there?

A

5: M, G, A, E and D

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

What heavy chains do each of the classes of Ig have?

A

Mu, gamma, alpha, epsilon and delta.

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

How many CH domains does the IgM heavy chain have?

A

4

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

How many antigen binding sites does the IgM class have?

A

10, pentameric 970 kDa.

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

What is the function on IgM?

A

The first antibody to be secreted in response to a foreign antigen- primary response which activates classical complement pathway. Mainly confined to the vascular system due to its size. Has high avidity for antigens as it has ten hinging sites and can also bind polyvalent antigens (eg. Bacterial surfaces).

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

What does IgG have?

A

4 distinct isotypes: 1, 2, 3 and 4.

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

What are the masses of the monomeric isotypes of IgG?

A

1, 2 and 4 are 146 kDa but 3 is 165 kDa.

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

How many CH domains do the heavy chains of IgG have?

A

3

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

What is the function of IgG?

A

A systemic antibody produced in secondary response to antigen by B-cells in the lymph nodes and spleen, activates the classical complement pathway, a major antibody in human blood, not confined to the blood stream, opsonises microbes for uptake by phagocytosis.

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

What is IgG role in pregnancy?

A

It is actively transported across the placenta into the foetus to protect newborns find the first 3-6 months.

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

How many CH domains does IgA heavy chain have?

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does IgA exist?

A

As both a monomer of 160 kDa and a dimer of 320 kDa.

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

What is the function go IgA?

A

Produced by B cells in the mucosal associated lymphoid tissues during the secondary immune response and transported to the mucus layer across the epithelium.

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

What is IgA poor at?

A

Opsonisation and complement activation, primary action is to neutralise antigens which therefore removes the need for opsonisation etc.

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

How does IgA neutralise antigens?

A

Prevents bacterial toxins from binding cellular targets, inhibits microbial adhesion to epithelia, inhibits viral infectivity.

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

How many CH domains does the heavy chain of IgE have?

A

4

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

What is the structure of IgE?

A

188 kDa monomer.

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

What is the function of IgE?

A

Usually produced in the mucosal associated lymphoid tissues, important in parasitic immune response and type 1 hypersensitivity responses. Found in low concentrations in the blood.

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

How many CH domains does the heavy chain of IgD have?

A

3

23
Q

What is the structure of IgD?

A

160 kDa monomer.

24
Q

What is the function of IgD?

A

Poorly understood, known to act as an antigen receptor on immature B-cells and is present in the blood at very low concentrations.

24
Q

Where is IgM found?

A

Mainly in blood but partially in the tissue fluid.

25
Q

Which Ig is found in most places and where are these?

A

IgG is found in the blood, tissue fluid and placental transfer.

26
Q

Where is IgA found?

A

Mostly in mucus secretion but also partially in the tissue fluid and blood.

27
Q

Where is IgE found?

A

Bound to mast cells.

28
Q

Where is IgD found?

A

Unknown

29
Q

What do naive B cells that exit the bone marrow express?

A

IgM and IgD

30
Q

What do B cells undergo as they mature?

A

Class switching: switch IgM and IgD for others.

31
Q

What is class switching?

A

Involves both the membrane immunoglobulin and the secreted immunoglobulin and it tailors the humoral response for a particular type of antigen and for its position in the body.

32
Q

What class would be predicted to be expressed in antigens in the blood and tissues?

A

IgG

33
Q

What class would be predicted to be expressed in antigens in mucus secretions?

A

IgA

34
Q

Parasitic and allergic response antigens would be predicted to express what class?

A

IgE

35
Q

What is an important feature or class switching?

A

Only the heavy chain constant regions are switched and the antigenic specificity is not altered as the light chain and the VH domains are retained.

36
Q

How is a vast repertoire of antibodies generated by B cells?

A

Somatic rearrangement, affinity maturation and class switching.

37
Q

What are the applications if antibodies?

A

Physiological role in fighting disease,
Research eg. detecting invisible substances or blocking function,
Diagnosis/prognosis eg. detecting disease markers, blood types and pregnancy hormones
Therapeutics eg. anti-venom, passive vaccination and immunotherapy.
Industrial uses eg. abzymes and detectors

38
Q

What is the difference between polyclonal and monoclonal antibodies?

A

Polyclonal antibodies are produced by many different B cells responding to the same antigen.
Monoclonal antibodies are produced by a population of identical cloned B cells and therefore respond to the same antigen.

39
Q

How are polyclonal antibodies produced?

A

An animal is immunised (usually a rabbit, goat or donkey) with purified protein and adjuvant which prompt antibody production. A whole sera, liquid fraction of clotted blood, is taken and purified.

40
Q

What is an adjuvant?

A

A pharma/immunological agent that modifies the effect of other agents. Usually Freund’s is used to elicit a local immune response.

41
Q

What are the advantages of polyclonal antibodies?

A

Technically easy to obtain, antibodies are against numerous epitopes which allows more effective cross-linking/neutralisation and a higher chance of cross-reactivity.

42
Q

What are the uses of polyclonal antibodies?

A

Physiological response, research, diagnosis, anti-venom, passive immunity and prevention of haemolytic disease of the newborn.

43
Q

What are disadvantages of polyclonal antibodies?

A

They cannot easily manipulate via recombinant means, each antisera preparation differs in their specificity, average affinity, cross reactive specificities etc., they are not optimised for application, and supply is limited.

44
Q

How are monoclonal antibodies generated?

A

Take a mouse, isolate a spleen cell, produce hybridomas, select one to clone to produce antibodies.

45
Q

What are the problems with mouse antibodies?

A

They’re immunogenic, mice need to be housed and killed, an antibody has to generated and cloned before manipulation and you cannot generate antibodies against very homologous proteins.

46
Q

How do you overcome the problems with mouse antibodies?

A

In vitro generation and phage display technology.

47
Q

What are the uses of monoclonal antibodies?

A

Research, diagnostic and prognostic indicators, abzymes, therapeutic antibodies, pregnancy tests etc.

48
Q

How do pregnancy tests work?

A

The test zone has monoclonal mouse anti-hCG* enzyme conjugate. The first line has fixed polyclonal anti hCG plus substrate and the second line has fixed anti-mouse IgG plus substrate. If both lines show the test is positive.

49
Q

What are problems with monoclonal antibodies?

A

Repeat doses are often immunogenic which results in neutralising anti-antibody antibodies (but not always due to immunogenicity), side-effects mediated via Fc region.

50
Q

What are magic bullets?

A

Recombinant antibodies with radioisotope, cytotoxic drug, toxin, antibody dimer, enzyme or bispecific antibody, to cause a further effect.

51
Q

What are the advantaged of monoclonal antibodies?

A

Consistent, there’s a limitless supply of specific reagent, more easily tested cross reactivity, can be optimised for application and they can be manipulated via recombinant technologies.

52
Q

What are the disadvantages of monoclonal antibodies?

A

Technically more difficult and time consuming, less likely to neutralise/cross react.

BIOC2301 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions