Brainscape's Knowledge GenomeTM

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


See full index

Immunology > Lecture 4 Slides effector responses > Flashcards

Lecture 4 Slides effector responses Flashcards

0
Q

Purpose of virus and toxin neutralization

A

Prevents pathogen-host binding

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

Four categories of antibody effector function

A

Virus and toxin neutralization
Opsonization
Complement fixation and formation of the membrane attack complex
Antibody-dependent cell-mediated cytotoxicity (ADCC)

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

Purpose of opsonization

A

Phagocytosis of bacteria

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

Purpose of complement fixation and formation of membrane attack complex

A

Phagocytosis or lysis

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

ADCC purpose

A

NK induced apoptosis

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

How neutralization works

A

Antibody binds to site on pathogen or toxin with host proteins, masking them, and inhibiting entry of that pathogen or toxin into the host, antibody-pathogen complexes are then eliminated, often after phagocytosis

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

How opsonization works

A

Antibody binds to pathogen and is then bound by Fc receptors on phagocytosic cells. The antibody-antigen binding to FcRs induces internalization and destruction by the phagocytic cell

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

How complement fixation works

A

Antibody-antigen complex becomes bound by complement components in serum and is either phagocytosed via cells expressing C3 receptors or lyses as a result of pore formation by the complement components C7,8,9

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

How does ADCC work

A

Antibody antigen complexes are bound by Fc receptors on NK cells and granulocytes, thus directing the cytotoxicity of these cells toward the antigen targeted by the antibody and inducing apoptosis of the target cell

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

Functions of Fc receptors

A 
De granulation (FccR and IgE)
Opsonization of bacteria and phagocytosis 
Maintaining serum levels of antibodies
ADCC
Trams cytosine into secretions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

On what four types of noncovalent forces so antigen antibody reactions depend? Are reactions reversible?

A

Hydrogen bonds
Ionic bonds
Hydrophobic
Van der Waals

Reactions are reversible

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

What do weak noncovalent interactions depend on to happen

A

Close Complementarity of the shapes of the antibody and antigen

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

Antibody-combining site

A

Cleft formed by heavy and light antibody chains where antigen molecule nestles

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

Where does antigen make contact with antibody

A

Amino acids in hyper variable regions of borh heavy and light chains

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

Antibody affinity

A

Combined forces that helps antibody bind antigen. Defined as a constant.

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

What is affinity the result of

A

A balance between the attractive and repulsive forces. High affinity implies good fit and vice versa. (Kb)

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

Antibody avidity

A

Affinity plus valence.

How strong plus how many arms to bind

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

Sensitivity

A

How little or how much antigen can be detected

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

Six antigen-antibody based assays

A
  1. Precipitation
  2. Agglutination
  3. Radioimmunoassay
  4. Enzyme linked immunosorbent assay (most widely used)
  5. Immunofluorescence/immunocytochemistry
  6. Flow cytometry
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Precipitation reaction

A

Antibody and soluble antigen (both soluble alone) interact in aqueous solution and form a precipitate

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

Precipitin

A

Antibody that can precipitate out of solution once bound to antigen

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

In precipitation reaction, antibody must be

A

Bivalent

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

In precipitation reaction, antigen can be

A

Bivalent or multivalent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Disadvantages of precipitation reaction

A

Slow, taking day or two
Requires large quantity of Ag or Ab
Replaced by modern assays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Radial and double immunodiffusion

A 
A precipitation reaction
Immune precipitate in gel
Ag and Ab diffuse towards each other
Visible line of precipitation occurs at the line of equilibrium
Only antigen diffuse in radial
Both Ag and Ab diffuse in double
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Radial immunodiffusion (Mancini)

A 
In gel
Circle
Antibody incorporated in agar
Antigen in center and diffuses
Precipitate forms a ring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Double (Ouchterlony) immunodiffusion

A

Antibody and antigen samples next to each other and can mix in middle, where thy form a precipitate. Both Ab and Ag diffuse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why can’t univalent antigens precipitate out of solution

A

They bind to antibody and nothing else. Can’t form lattice.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Levels of precipitation reaction

A

Antibody excess zone
Equivalence zone
Antigen excess zone

29
Q

Why does excess antigen lead to a reduction in the amount of antibody precipitated

A

Fall is due to solubilization of antigen-antibody complexes by excess antigen.

30
Q

Immuno-double-diffusion line of identity

A

Single constant line between Ab and two antigen samples tested

31
Q

Line of nonidentity

A

No constant line, but lines that cross form

32
Q

Line of partial identity

A

A continuous line exists, but with a spur, indicating that complex is related but not identical

33
Q

Coggin’s test

A

Example od Immuno-double-diffusion

34
Q

Immunoelectrophoresis

A

Combines electrophoresis and double immunodiffusion
Antigen mixture is first electrophorised to separate its component by charge
Specific antibody and antigen will diffuse and produce line precipitation
Qualitative study (rocket immunoelectrophoresis)
Reduces time and forces reaction.

35
Q

Immunoelectrophoresis steps

A

1.separate antigens in an agar gel by placing electric charge across it.
The gel’s pH is chosen so that positively charged proteins move to negative electrode and negative to the positive.
2. A trough is then cut between the walls and filled with the antibody, which is left to diffuse
3. The antigens and antibody form precipitin arcs

36
Q

Immunoprecipitation

A

Collect immunoprecipitates using magnetic beads coupled to secondary antibody

37
Q

Immunoprecipitation steps

A
  1. Treat cell extract with antigen by placing antibody so complex forms
  2. Add magnetic beads to which second antibody is linked. This binds to complex.
  3. Place magnet against side of tube to collect antigen-antibody complexes
  4. Rinse
  5. Dissociate to study antigen
38
Q

Agglutination

A

Visible clumping formed by the interaction between Ab and a particulate Ag

39
Q

Agglutinin

A

Antibody

40
Q

Solubility in agglutination

A

One is soluble. One is insoluble. Nothing is precipitating out of solution. We are looking for a complex.

41
Q

Uses of agglutination

A

Widely used
Used to detect blood type
RBCs mixed with anti sera to A or B antigen
Bacterial agglutination
Passive agglutination (coating RBC antigen and add serum)

42
Q

Agglutination inhibition

A

Absence of agglutination is diagnostic of antigen

43
Q

Blood type A has which antigens and antibodies

A

Antigens A

Ab anti-B

44
Q

Blood type B has which antigens and Ab

A

b and anti-A

45
Q

AB has which antigens and antibodies

A

A and B. Neither

46
Q

O has which antigens and antibodies

A

Neither antigen. Anti-A and anti-B

47
Q

Hemagglutination assay

A

Used for certain viruses

Hemagglutination is positive

48
Q

Radioimmunoassay (RIA)

A

Immunoassay for antibody
Most sensitive technique for detecting Ag or Ab
A labeled and unlabeled Ag compete for the Ab binding site
Ag is labeled with radioisotope, added to Ab and the test Ag is added
Displaced radioactive isotope is measured

49
Q

For what is radioimmunoassay used

A

Detecting hormones

50
Q

Radioimmunoassay steps

A
  1. Labeled Ag and unlabeled Ag are mixed with Ab (infected because of unlabeled)
  2. Make uninfected batch, only labeled Ag
  3. Allow for incubation period
  4. Remove supernatant and measure radioactivity of antigen-antibody complexes
  5. If sample is infected, the amount of label bound will be less than in controls with uninfected serum
51
Q

Obtaining standard radioimmunoassay curve

A

Add increasing concentrations of unlabeled antigen to a fixed quantity of labeled Ag and antibody. Notice that amount of labeled Ag decreases as amount of unlabeled AG increases.

52
Q

Determine amount of unlabeled antigen with this curve

A

Concentration of unlabeled antigen can be determined by using linear part of course. How? Well, the amount of labeled displaced, wchi can be measured because of radioactivity, is equal to amount of unlabeled put in.

53
Q

Elisa

A

Similar to RIA with enzyme rather than radioactive labeling

An enzyme conjugated with an antibody reacts with a colorless substrate to generate a colored reaction product

54
Q

How to solve false positives with Elisa

A

Confirm positive with western blotting. Western blotting is highly specific. Elisa highly sensitive.

55
Q

Elisa stands for

A

Enzyme-linked immunosorbent assay

56
Q

Is Elisa quantitative or qualitative

A

Both

57
Q

ELISA steps

A
  1. Sensitize plate with antigen
  2. Wash
  3. Add test antibody
  4. Wash
  5. Add ligand
  6. Wash
  7. Add Chromogen
  8. Develop plate
58
Q

ELISA ligand

A

A molecule that can detect the antibody and is covalently coupled to an enzyme such as peroxidase. This binds test antibody. After free ligand is washed away, bound ligand is visualized by addition of chromogen

59
Q

Chromogen

A

A colorless substrate which is acted on by the enzyme portion of the ligand to produce a colored end product.

60
Q

ELISA: how is amount of test antibody measures

A

By assessing the amount of colored end product by optical density scanning of the plate

61
Q

Indirect ELISA

A 
Antibody determined
Steps
-antigen coated well
-wash
-add specific antibody to be measured
-wash
-add enzyme-conjugated secondary antibody
-wash
-add substrate and measure color
62
Q

Sandwich ELISA

A 
Antigen is determined
Steps
-antibody coated well
-wash
-add antigen to be measured
-wash
-add enzyme conjugated secondary antibody
-wash
-add substrate and measure color
63
Q

Competitive ELISA

A

inhibition type assay
Concentration of antigen is inversely proportional to the color produced
STEPS
-incubate antibody with antigen to be measures
-add Ag-Ab mixture to antigen-coated well
-wash
-add enzyme conjugated secondary antibody
-wash
-add substrate and measure color

64
Q

Immunofluorescence

A

Fluorescence molecules absorb light of one wavelength and emit light with another wavelength
The emitted light can be viewed with fluorescence microscope

65
Q

Immunofluorescence types

A
  1. Direct
  2. Indirect with fluorochrome-labeled anti-isotype antibody
  3. Indirect method with fluorochrome-labeled protein A
66
Q

Direct immunofluorescence

A

Primary Antibody to mAg is labeled with fluorochrome

Primary antibody binds directly to antigen

67
Q

Indirect method immunofluorescence

A

Primary antibody bonds to antigen
Fluorochrome is used to label secondary anti-isotype antibody, which binds to primary antibody OR
Fluorochrome is used to label protein that binds to antibody Fc portio

68
Q

Two techniques used to localize viral antigens in tissues

A

Immunofluorescence

Immunohistochemistry

69
Q

Flow cytometry

A

Designed to automate analysis and separation of cells stained with fluorescent dye
Uses laser beam and light detector to count intact cells in suspension
Quantitative whereas immunofluorescence is qualitative only

Immunology (5 decks)

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