Immunoglobulins Flashcards

1
Q

The 3 most abundant plasma proteins

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

Antigen

A

Any foreign molecule bound selectively by antibodies

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

Immunogen

A

Molecule (protein, carbohydrate, nucleic acid) that induces antibody production

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

Antigenic determinant/ epitope

A

Small region of a larger molecule (like a protein) that elicits the production of a specific antibody

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

There are __ peptide chains in an antibody

___ holds the 2 heavy chains of an antibody together and a light chain to the heavy chain.

Within the ___ chain there are 3 constant domains and 1 variable domain.

A

4 peptide chains

Disulfide bonds.

The heavy chain has the 3 constant domains (CH1-CH3) and 1 variable domain (VH); defines the class of immunoglobulin

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

The light chain can be one of two types

A

lambda or kappa

Both have constant (CL) and variable (VL) regions

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

The variable domains from both the heavy and light chains all face to one end of the molecule and serve as

A

antigen binding sites to the specific epitopes

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

The five immunoglobulin classes GADEM all have different ___ chains.

Match the chain with teh class.

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

Which Igs contain multiples of the 2heavychain,2lightchain tetramer?

A

IgA is a dimer

IgM is a pentamer

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

The individual constant and variable domains are supersecondary structures.

Describe the Immunoglobulin fold in constant domains vs variable domains

A

Each domain is composed of B-strands that form anti-parallel B-sheets.

  • Constant domains* - 7 strands held together in a 4-3 arrangement by hydrogen bonds or hydrophobic interactions between the R groups.
  • Variable domains* - 9 strands held together in a 5-4 arrangement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Complementarity Determining Regions

What are they and where are they?

A

Area of hypervariable amino sequence that is complementary to the epitope; serve as antigen-binding sites.

In the variable region of antibody light and heavy chains; they’re in the loops that connect the antiparallel B strands (3 loops from light chain, 3 loops from heavy chain)

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

The combine dvariability of the 12 CDR sites from all 4 peptide chains provides the diversity for

A

antibody:epitope interactions

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

The regions between CDRs are called

A

Framework regions

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

Steps of an ELISA immunoassay

A

ELISA shows the quantitation of any protein in a sample

The primary antibody is specific for the protein/antigen of interest.

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

ChIP

Purpose & steps

A
  • Purpose
    • Demosntrates whether specific proteins are associated with specific regions on the genome
    • Determines specific locations in the genome where epigenetic modifications occur
  • Steps
    • Crosslink protein to DNA
    • Shear DNA into short pieces
    • Use antibodies to immunoprecipitate proteins from the mixture
    • Sequence the immunoprecipitated DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Polyclonal vs Monoclonal antibodies

A

Polyclonal antibodies are produced by B lymphocytes in response to antigens; it’s a range of different antibodies that recognize all the different epitopes on the target antigen.

  • Occurs in your body all the time

Monoclonal antibodies: synthesized by a population of identical B lymphocytes in a cell culture all producing antibodies to only one epitope; it’s a homogenous antibody population that all recognize tehs ame epitope.

  • Used for therapy against one epitope
17
Q

Myelomas

A
  • Cancer of plasma cells (B-lymphocytes that secrete Igs)
  • Elevated Ca2+, renal failure, anemia, bone lesions (CRAB)
  • Markers
    • High serum [monoclonal antibody/Mprotein]
    • Urinate Bence Jones protein (monoclonal light chains)
18
Q

Producing monoclonal antibodies: how can cells making antibodies against one specific epitope be isolated from the rest of the B cells in the polyclonal population and also be made immortal (myeloma cells)?

A
  1. Inject an antigen into a mouse to produce a polyclonal population of antibodies against the antigen
  2. Remove and fuse the spleen cells with myeloma cells, which are engineered to be HGPRT negative (won’t grow in a HAT medium)
  3. Spleen cells that can’t fuse with myeloma cells will die because they are mortal; myeloma cells will die since they can’t grow in the HAT medium
  4. Only the hybridomas (antibody-producing spleen cells + immortal myeloma cells) can grow in the HAT medium
  5. Titrate the survivors so no more than 1 cell in a single well and let them grow.
  6. Assay the supernatant for an antibody against the antigen of interest and then clone –> monoclonal populations
19
Q

Our monoclonal antibody may be very specific for the target epitope, but humans would hae an immune response to a mouse Ig.

how did we address this?

A

Chimeric monoclonal antibody: variable domain from mouse, but the rest is from humans

mouse hypervariable CDRs cloned in-frame to the human framework for both light and heavy chains

20
Q

If something ends in -mab, what is it?

A

Monoclonal antibody .

A drug ending in -mab is an antibody-based therapeutic agent

21
Q

Western blots / Immunoblots

A
  1. Separate proteins on SDS gels
  2. Transfer to membrane
  3. Block membrane with nonspecific protein
  4. Incubate with primary antibody
  5. Incubate with antibody-enzyme that binds to primary antibody
  6. Add substrate
  7. Colored product precipitates on membrane where the specific protein is located
22
Q

Most abundant plasma protein

A

albumin

23
Q

Most abundant immunoglobulin in plasma

A

IgG

24
Q

The antigen binds at the __ terminal of the antibody

A

N

25
Q

Where in this molecule is a protease most likely to attach?

Also recognize the diff regions

A

Hinge region