Brainscape's Knowledge GenomeTM

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


See full index

MDSC 321 > Lecture 14-15: Antigens > Flashcards

Lecture 14-15: Antigens Flashcards

1
Q

The innate immune system recognizes PAMPs what does the adaptive immune system recognize?

A

Antigens

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

What is an antigen (define)

A

Any molecule that can interact with the immunoglobulin receptor of B cells or the T cell receptor

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

Define immunogen

A

A molecule that induced a specific immune response

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

Finish the sentence, all immunogens are…

A

Antigens

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

Are all antigens immunogens?

A

No, not all antigens cause an immune response

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

Define haptens

A

Small antigenic molecules that can’t produce an immune response on there own

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

What molecules do a B cell respond to? The immunogens

A

Proteins»Polysaccharides»Lipids or nucleic acids

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

What molecules do a T cell respond to? The immunogens

A
  • Proteins, some lipids, some glycolipids

- proteins are not recognized on their own and need to have a MHC molecule attached

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

What kind of immunity are B cells

A

Humoral

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

What kind of immunity are T cells

A

Cell mediated

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

What are the 4 properties of an antigen/immunogen?

A
  1. An immunogen must be non self and the more non self it is the better response it’ll produce
  2. The bigger the molecule the better the response
  3. Proteins with more structure increase immunogenicity.
  4. Proteins must be degraded to activate T cells so factors that affect this are; insoluble, large, L amino acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is antigen tolerance?

A

Too high or too low a dose of antigens

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

What is the route of administration and how does it affect the immune response?

A

Intravenous, intramuscular, intradermal etc which influences the immune response

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

What are adjuvants?

A

Substances that are injected with antigens and enhance the immune response

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

Review adjuvant mechanisms on paper

A

I did

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

What do B and T lymphocytes recognize?

A

Small sites called epitopes

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

How do B-cell epitopes work? (2)

A
  • they bind the antigen directly via antibodies

- they recognize almost any antigen

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

What is immunodominance

A

When not all epitopes induce a response

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

What is a linear and a conformational epitope and which lymphocyte can see which?

A
  • linear is when there isn’t any two lines touching just one single line
  • conformational is when two lines intersect
  • B cells can see both
  • T cells can only see one
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What antigens can a T cell recognize and what must be done to an antigen for a T cell to recognize it?

A
  • only protein and some glycolipids
  • antigen has to be processed
  • antigens peptide fragments must be presented in association with major histocompatibility complex molecules
  • peptide must be amphipathic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does it mean to be amphipathic and how does this relate to T cell antigens?

A

The peptides must be amphipathic to be recognized. Meaning they need a hydrophobic and hydrophilic region to bind to MHC and TCR respectively

22
Q

What is the agretope?

A

MHC binding site of an antigen

23
Q

What is the epitope called on a T cell?

A

TCR binding site of an antigen

24
Q

Do B cells and T cells have soluble antigens?

A

B cells do, T cells do not

25
Q

What can a B cells epitope recognize

A

Hydrophilic, sequential or conformational

26
Q

Compare linear epitopes and conformational epitopes

A
  • linear epitopes are stable during protein reduction and denaturation
  • conformational epitopes are destroyed through reduction and denaturation
27
Q

What are antigen antibody interactions like?

A

Highly specific binding between molecules

28
Q

What is antigen-antibody specificity determined by?

A

Specificity is determined by multiple low affinity non-covalent bonds such as;

  • ionic bonds
  • hydrogen bonds
  • van der waals interactions
  • hydrophobic bonds
29
Q

Define affinity

A

It is the strength of the sum of interactions between a single antigen binding site on an antibody and a single epitope

30
Q

What is the formula for association constant Ka

A

Ka=[Ab-Ag]/[Ab][Ag], concentration of Ag-Ab complex

31
Q

What is the value of low affinity Ab-Ag binding?

A

Ka=10^4 - 10^5 M^-1

32
Q

What is the value of high affinity Ab-Ag binding?

A

Ka=10^10 - 10^11 M^-1

33
Q

How does the concentration of antigens vs antigens with antibodies work?

A
  • antigens on their own diffuse equally

- antigens with antibodies diffuse equally then bind to antibodies so more antigens diffuse in

34
Q

What is avidity?

A

The strength of multiple interactions between multivalent antibody and antigen. High affinity can compensate for low affinity

35
Q

What is affinity and avidity dictated by?

A

By the Ag/Ab fit and dictated by affinity and the number of Ag/Ab bindings

36
Q

Draw what low and high affinity and avidity looks like?

A

I did

37
Q

What is antigen cross reactivity?

A
  • different antigens may have the same epitope which can be bonded by the same antibody
  • epitopes can be different but have similar chemical properties
38
Q

What are anti-A bodies?

A

Epitopes are similar to an enzyme on A from ABO blood

39
Q

What are anti-B bodies?

A

Glycoproteins on bacteria that resemble an enzyme on the B from ABO blood

40
Q

When does precipitation occur?

A

Ag-Ab interactions result in the formation of a lattice structure which requires at least a bivalent and bivalent or polyvalent antigen

41
Q

What inhibits precipitation?

A

Excess of either antibodies or antigens

42
Q

What is the zone of equivalence?

A

The maximal precipitation that is achieved in a zone of optimal antigen and antibody concentration

43
Q

What is precipitation?

A

Like chemistry, when two soluble compounds come together to make an insoluble compound

44
Q

What are the three theories for why antibodies can bind and recognize so many antigens?

A
  • selective (side chain) theory
  • instructional theory
  • two gene theory
45
Q

What was the selective side chain theory?

A

Antibodies express multiple side chains of various antigen specificity and when an antigen interacts with a side chain more of the side chains are made. It can be disproved however

46
Q

What is the instructional theory?

A

The antibody takes a shape that compliments the antigens however how do you account for specificity before exposure to the antigen?

47
Q

What is two gene theory?

A

Two genes encode the antibody, one for the variable region and one for the constant region. Many different variable genes which accounts for the diversity produced and only a few constant genes.

48
Q

What experiment proved the two gene theory?

A

Analysis of antibody genes from cancer cells and embryonic cells demonstrated DNA differences.

49
Q

What are the gene segments that make an antibody?

A
  • light chain variable region (κ, λ)

- heavy chain variable region

50
Q

What is the light chain region composed of?

A

A variable (V) and a joining (J) gene segments

51
Q

What is the heavy chain region composed of?

A

A variable (V), joining (J) and diversity (D) gene segments

MDSC 321 (21 decks)

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