ImmunoSero Lab (Midterm - Ag & Ab Reaction) Flashcards

1
Q

Specificity of antigen-antibody reactions

A

highly specific

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2
Q

reacts only with antibodies produced by itself or with closely related antigens

A

antigens

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3
Q

Recognize molecular shapes (epitopes) on antigens

A

Antibodies

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4
Q

The ____________ fit of the epitope, the more ____________ the interactions will be formed between the antibody and antigen and the ____________ the affinity of the antibody for antigen.

A

better fit
more favourable interactions
higher affinity

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5
Q

Salient features of Ag-Ab Reaction

A
  1. Specificity of antigen-antibody
  2. Immune complex
  3. Binding site of antigen-antibody reaction
  4. Binding force of antigen-antibody reaction
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6
Q

Salient feature of Ag-Ab Reaction:

Each antibody binds to a specific antigen where its interaction is similar to lock and key.

A

Specificity of antignen-antibody

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7
Q

Salient feature of Ag-Ab Reaction:

  1. Ag + Ab —> Ag-Ab complex
  2. Molecule formed from the binding of multiple
    antigens to antibodies
  3. The bound antigen and antibody act as a
    unitary object, effectively an antigen of its
    own with a specific epitope
A

Immune complex

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8
Q

Salient feature of Ag-Ab Reaction:

In Ag-Ab reaction, the Ab attaches with the
Antigen

A

Binding site of antigen-antibody reaction

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9
Q

The part of the antigen which combines with the antibody which is also known as antigenic determinant

A

epitope

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10
Q

The epitope is recognized by the immune system, specifically by:

A

Antibodies
B cells
T cells

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11
Q

The part of the antibody that recognized the epitope

A

Paratope

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12
Q

3 Factors (Binding force of Ag-Ab reaction)

A
  1. Closeness between Ag and Ab
  2. Affinity of antibody
  3. Non-covalent bonds of intermolecular forces
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13
Q

When antigen and antibody are ____________ the strength of binding is great; when they are ____________ binding strength is low.

A) apart; closely fit
B) closely fit; apart

A

B) closely fit; apart

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14
Q

These bonds hold the antigen to the antibody combining site

A

Noncovalent bonds

These include:
Hydrogen bonds
Electrostatic bonds
Van der Waals forces
Hydrophobic bonds

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14
Q

Strength of the reaction between a single antigenic determinant and a single combining site on the antibody

A

Affinity

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15
Q

Properties of antigen-antibody reactions

A
  1. Antibody affinity
  2. Antibody avidity
  3. Cross Reaction
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16
Q

Measure of the binding strength at a single binding site

A

affinity

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17
Q

Measure of total or overall strength

A

avidity

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18
Q

Application of Ag-Ab reaction:
(DDD ST)

A
  1. Determination of blood groups for transfusion
  2. Determining the characteristics of certain immunodeficiency disease
  3. Development of immunoassays for the quantification of various substances
  4. Serological exposure to infectious agents
  5. To detect the presence or absence of protein in serum
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19
Q

Types of Ag-Ab Reactions:
APICE IRI

A
  1. Agglutination
  2. Precipitation
  3. Immunofluorescence
  4. Complement fixation
  5. ELISA
  6. Immunofixation
  7. Radioimmunoassay
  8. Immunoelectrophoresis
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20
Q

A type of reaction when a particular Ag is mixed with its Ab’s in the presence of electrolytes at a suitable temperature and pH; the particles are clumped or agglutinated

A

Agglutination

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21
Q

The Ab of the serum causes the cellular Ag’s to form clumps and these are called

A

agglutinins

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22
Q

The participate antigens that are aggregated

A

agglutinogens

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23
Q

Rapid method to determine the presence of agglutinating antibodies

A

Slide agglutination

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24
Q

This is a standard method for quantitative estimation of Ab

A

Tube agglutination

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25
Q

This is the test used for blood grouping and cross matching

A

slide agglutination

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26
Q

This indicates that test in slide agglutination is positive

A

granulation

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27
Q

The tube showing highest agglutination

A

Titer

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28
Q

Employed for the serological diagnosis of Typhoid, Brucellosis, Typhus fever

A

Tube agglutination

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29
Q

Agglutination Principle

A

Particulate + antibody
Lattice formation

30
Q

Antigen binds with FAB sites of two antibodies forming bridges between antigens resulting to clumping

A

Lattice Formation

31
Q

Direct agglutination

A

Blood Banks

32
Q

In passive hemagglutination, this is used to treat RBCs to allow adsorption of protein antigens

A

tannic acid

33
Q

Antigen in reagent is attached to latex particle

A

Passive latex agglutination

34
Q

Steps for agglutination inhibition

A

Step 1: Patient serum (antigen) is reacted with limited amount of antibody reaction
Step 2: Indicator is added (same antigen for which you are testing bound to RBC or latex carrier particle

35
Q

A positive test for agglutination inhibition

A

no agglutination

36
Q

Negative test for agglutination inhibition

A

agglutination

37
Q

Inhibition reactions:

Q1: Hemagglutination inhibition test is for ….

Q2: Latex agglutination inhibition test is for …

A

Rubella B.; other viruses respectively

38
Q

When a soluble Ag combines with its Ab in the presence of an electrolyte (NaCl) at a particular temperature and pH. It forms an insoluble precipitate of Ag-Ab complex

A

Precipitation

39
Q

The antibody causing precipitation

A

Precipitin

40
Q

Reaction of precipitin

A

precipitation reaction

41
Q

Precipitation principle

A

soluble antigen + antibody
Lattice formation

42
Q

Antigen binds with Fab sites of two antibodies and a visible precipitate is observed.

A

Lattice formation

43
Q

Double diffusion

A

ouchterlony

44
Q

Single diffusion

A

Radial immunodiffusion

45
Q

Examples of precipitation reaction

A

Double diffusion
Single diffusion
Immunoelectrophoresis
Immunofixation

46
Q

Nonspecific unstable components of fresh serum for lysis of RBC or bacteria

A

complement

47
Q

Steps for complement fixation

A
  1. Antibody and antigen allow to combine in presence of complement
  2. Indicator is added (SRBC coated with hemolysin)
48
Q

Positive and negative test for complement fixation

A

Positive: no hemolysis
Negative: hemolysis

49
Q

Limitations of complement fixation
1. Serum must be ____________________
2. Stored serum becomes ____________
3. Elaborate ________________ and ________________ required
4. Only used for ________________ antibodies

A
  1. Serum must be heat inactivated
  2. Stored serum becomes anticomplementary
  3. Elaborate QC and standardization required
  4. Only used for IgMantibodies
50
Q

Complement is inactivated by

A

heating to 56oC for 30 minutes or after 4 hours reinactivated by heating for 10 minutes

51
Q

Sandwich technique

A

Enzyme Link Immunoassay (EIA/ELISA)

52
Q

Antibodies involved in ELISA

A

Monoclonal and Polyclonal antibodies

53
Q

Monoclonal or polyclonal antibody are adsrobed on this surface

A

solid surface (bead or microtiter well)

54
Q

Its presence in serum binds to antibody-coated bead or well

A

antigen

55
Q

Forms antigen-antibody labelled antibody “sandwich”

A

Antibody conjugate (?)

56
Q

Antibody in conjugate is ________________ against another epitope of antigen being assayed.

A

directed

57
Q

Important in ELISA for each step to avoid false positive results

A

Washing (Proper)

58
Q

In ELISA, absorbance is ________________ proportional to antigen concentration.

A

directly

59
Q

Examples of ELISA application (HATS)

A

HIV testing
Serum HCG -pregnancy
Tests for hepatitis Ag and Ab
Antibodies to bacteria and viruses

60
Q

Property of absorbing light rays of one particular wavelength and emitting rays with a different wave length.

A

fluorescence

61
Q

show up brightly under UV
light as they convert into visible light

A

Fluorescent dyes

62
Q

Added to patient tissue in direct immunofluorescence (IF)

A

fluorescein-labelled antibody

63
Q

Added to patient serum and reagent in Indirect immunofluorescence

A

fluorescein labelled antiglobulin

64
Q

Examples of Indirect immunofluorescence

A

A. Testing for Antinuclear Antibodies (ANA)
B. Fluorescent Treponemal Antibody Test (FTA-Abs)

65
Q

Very sensitive and specific used for detecting antigen or antibody

A

Radioimmunoassay (RIA)

66
Q

Unlabelled and labelled antigen compete for binding with antibody

A

Competitive binding assay

67
Q

Done to remove unbound antigen

A

Wash

68
Q

The ________________ the radioactive count, the ________________ the concentration of unlabelled antigen.

A

Lower, higher

69
Q

A series of points that are arranged in a distinct pattern

A

lattice

70
Q

Nonlattice (More Sensitive)

A

Immunoassays
RIA (Radial immunoassay)
EIA (Enzyme immunoassay)
FIA (Fluorescent immunoassay)

Nepholometry

71
Q

Lattice (Less sensitive)

A
  1. CIE (Counter Current Immunoelectrophoresis):
    CF - complement fixation
    Agglutination
    Flocculation (precipitation)
  2. Rocket eletrophoresis
  3. RID (Radial immunodiffusion)
  4. Ouchterlony (Double immunodiffusion)
  5. IFE (Immunofixation)
  6. IEP (Immunoelectrophoresis)
72
Q

Value for nonlattice (more sensitive)

A

0.001 mg/ml

73
Q

Value for lattice (less sensitive)

A

500 mg/ml