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IMMUNOHEMA OFFSEM PM > TOPIC 3 - P1 > Flashcards

TOPIC 3 - P1 Flashcards

1
Q

Antihuman Globulin Test AKA ________

A

Coombs’ test

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2
Q

Principle: antihuman globulins (AHGs) obtained from immunized nonhuman species bind to human globulins such as IgG or complement, either free in serum or attached to antigens on RBCs

A

Coombs’ test

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3
Q

2 major types of blood group antibodies

A

IgM and IgG

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4
Q
  • large pentamer structure
  • directly agglutinate RBCs suspended in saline
A

IgM

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5
Q
  • termed nonagglutinating, or incomplete antibodies,
  • monomer structure is too small to directly agglutinate sensitized RBCs
A

IgG

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6
Q

AHG that contains _____ to RBCs sensitized with IgG antibodies allows for ______ of these sensitized cells

A

anti-IgG ; hemagglutination

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7
Q

_____ detect IgG or complement-sensitized RBCs

A

Antiglobulin tests

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8
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

Before, only _______ were detected. AGT permitted the detection of nonagglutinating IgG antibodies and led to the discovery and characterization of many new blood group systems.

A

IgM antibodies

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9
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

_____, Coombs and associates described the use of the _______ for the detection of weak and nonagglutinating Rh antibodies in serum

A

1945 ; antiglobulin test

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10
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

_____, Coombs and coworkers described the use of _____ to detect in vivo sensitization of the RBCs (later AKA direct antiglobulin test [DAT]) of babies suffering from __________

Although the test was initially of great value in the investigation of _____, its versatility for detecting other IgG blood group antibodies soon became evident.

A

1946 ; AHG ; hemolytic disease of the newborn (HDN)

Rh HDN

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11
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

weeks after Coombs had described the test, _________ antibodies and the associated antigen were reported

A

Kell blood group system

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12
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

Although Coombs and associates were instrumental in introducing the antiglobulin test to blood group serology, the principle of the test had in fact been described by ____ in ____

A

Moreschi ; 1908

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13
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

1908: Moreschi’s studies used ________ serum to agglutinate rabbit RBCs that were sensitized with low nonagglutinating doses of _________

A

rabbit antigoat ; goat antirabbit RBC serum

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14
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

Early AHG reagents: prepared using a -___________ as the immunogen

A

Crude globulin fraction

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15
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

______: _______ demonstrated that the antibody activity that detected Rh antibodies was associated with the ________ fraction in the reagent

A

1947 ; Coombs and Mourant ; anti–gamma globulin

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16
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

______: _____ presented the first indication that there might be another antibody activity present that influenced the final reaction

A

1951 ; Dacie

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17
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

observed that different ________ were obtained when dilutions of AHG were used to test cells sensitized with _____ as compared with cold antibodies

A

reaction patterns ; warm

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18
Q

(HISTORY OF THE ANTIGLOBULIN TEST)

_____: Dacie and coworkers published data showing that the reactivity of AHG to cells sensitized with warm antibodies resulted from _________ & ________ was responsible for the activity of cells sensitized by cold antibodies

A

1957 ; anti–gamma globulin activity ; anti–nongamma globulin activity

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19
Q

____________ was shown to be beta globulin and had specificity for complement

A

nongamma globulin component

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20
Q

Sensitization can occur either _____ OR ______

A

in vivo or in vitro

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21
Q
  • two-stage technique (With Incubation)
  • use of AHG to detect in vitro sensitization
    of RBCs
A

Indirect Antiglobulin Test (IAT)

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22
Q
  • one-stage procedure (Without Incubation)
  • use of AHG to detect in vivo sensitization of RBCs
A

Direct Antiglobulin Test (Dat)

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23
Q

Antihuman Globulin Reagents can be:

A

can be polyspecific or monospecific

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24
Q
  • contain antibody to human IgG and to the C3d component of human complement
  • can facilitate agglutination when RBCs have been sensitized with IgG or C3d or both.
A

Polyspecific AHG reagent

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25
Q

the disadvantage of this reagent is that, it may contain antibody activity to kappa and lambda light chains common to all immunoglobulin classes, thus reacting with IgA or IgM molecules

A

Polyspecific AHG reagent

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26
Q
  • contain only one antibody specificity: either anti-IgG or antibody to specific complement components [C3b or C3d (i.e., anticomplement)]
  • Anti-IgG: contain no anticomplement activity
  • contain antibodies specific for the FC
    fragment of the gamma heavy chain of the IgG molecule
  • Anticomplement: reactive against only the designated complement components
  • contain no activity against human immunoglobulins
  • often a blend of monoclonal anti-C3b and monoclonal anti-C3d
A

Monospecific

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27
Q

(Preparation of AHG)

classic method of AHG production involves injecting ______ or _______ into laboratory animals such as rabbits

human globulin behaves as _______ the rabbit’s immune response is triggered, and an antibody to human globulin is produced

A

human serum ; purified globulin

foreign antigen

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28
Q

(Preparation of AHG)

_______: mixture of antibodies from different plasma cell clones

recognize different _________ (epitopes), or the same portion of the antigen but with different affinities

A

Polyclonal antibodies ; antigenic determinants

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29
Q

(Preparation of AHG)

________: derived from one clone of plasma cells and recognize a single epitope

Uses ________

A

Monoclonal antibodies ; hybridoma technology

30
Q
  • one that contains both anti-IgG and anticomplement activity at the correct potency for immediate use
  • made using polyclonal or monoclonal antibodies
A

Polyspecific AHG

31
Q

Contains only one antibody specificity

A

Monospecific AHG

32
Q

immunizing 1 colony of rabbits with human immunoglobulin (IgG) antigen & another colony with human C3 antigen

A

Polyclonal AHG Production

33
Q

using serum from many donors to prepare the pooled IgG antigen to immunize the rabbits and the pooling of anti-IgG from many immunized rabbits

->essential in producing polyclonal reagents

A

Polyclonal AHG Production

34
Q

Polyclonal AHG Production process

(1) colonies of animals are ______ to produce high-titer, high-avidity IgG antibodies

A

hyperimmunized

35
Q

Polyclonal AHG Production process

(2) if the antibody ______ and _____ meet predetermined specifications, the animals are bled for a production batch of reagent

A

potency and specificity

36
Q

Polyclonal AHG Production process

(3) Separate blends of the ______ and _______ antibodies are made

A

anti-IgG and anticomplement

37
Q

Polyclonal AHG Production process

(4) each pool is then absorbed with ____, ____, and ____ cells to remove _______ antibodies

A

A1, B, and O ; heterospecific

38
Q

Polyclonal AHG Production process

(5) Total Ab content of each pool is determined, and potency of the pools is analyzed to calculate the _______ for use.

A

optimum Ab dilution

39
Q

Polyclonal AHG Production process

(6) Block titrations for anti-IgG pools are performed by reacting dilutions of each antibody against cells ___________

–> critical step in the manufacturing process because excess antibody may lead to _____ hence, false-negative test results

A

; sensitized with different amounts of IgG

; prozoning

40
Q

Polyclonal AHG Production process

(7) potency of anti-C3 pools is measured using at least two examples each of a _____ and ______

A

C3b- and C3d-coated cell

41
Q

(Polyclonal AHG Production)

advantage of using anti-IgG of polyclonal origin: ____________

A

capable of detecting the many different IgG Ab

42
Q

Immunization of laboratory animals, usually mice.

A

Monoclonal AHG Production

43
Q

using with purified human globulin

A

Monoclonal AHG Production

44
Q

Monoclonal AHG Production Process

(1) Immunization of laboratory animals, usually ____, with purified human globulin

A

mice

45
Q

Monoclonal AHG Production Process

(2) Mouse spleen cells containing antibody-secreting lymphocytes + myeloma cells=“_______”

A

hybridomas

46
Q

Monoclonal AHG Production Process

(3) Hybridomas screened for antibodies with the required ______ and _______

A

specificity and affinity

47
Q

Monoclonal AHG Production Process

(4) antibody-secreting clones may be ______ in tissue culture or by ______ into mice (antibody is collected as ______)

A

propagated ; inoculation ; ascites

48
Q

Monoclonal AHG Production Process

(5) no need for _____ to remove heterospecific antibodies

A

absorption

49
Q

Monoclonal AHG Production Process

(6) All antibody molecules produced identical in terms of ________ and _______

A

antibody structure and antigen specificity

50
Q

advantage of using anti-IgG of monoclonal origin: once an antibody-secreting clone of cells has been established, antibody with the same _______ and _____ will be available indefinitely

->allows the production of a consistently pure and uncontaminated _____

A
  • specificity and reaction characteristics
  • AHG reagent
51
Q

disadvantage of monoclonal ahg production is that all antibodies produced by a clone of cells recognize a _______ present on an antigen

A

single epitope

52
Q

Antibodies Required in AHG

A

(1) Anti-IgG
(2) Anticomplement

53
Q

(Anti-IgG)

majority of these antibodies: mixture of ____ and ______

A

IgG1 and IgG3 subclass

54
Q

(Anti-IgG)

Rarely: _________ antibodies may be found

shown to fix ______ and may be detected by _______

A

nonagglutinating IgM

; complement , anticomplement

55
Q

(Anti-IgG)

only RBC alloantibodies as solely IgA have been examples of _____

A

anti-Pr

56
Q

(Anticomplement)

Some antibodies “fix” _______ to the RBC membrane after complexing of the antibody with its corresponding antigen

A

complement components

57
Q

(Anticomplement)

____. _____ and ____ in the table refer to antibodies that bind complement the vast majority of the time, that show variability in their ability to bind complement, and that rarely bind complement, respectively

A

most, some, and rare

58
Q

ANTIBODIES CAPABLE OF BINDING COMPLEMENT

(MOST)

A

ABO
Le(a)
Le(b)
Jk(a)
Jk(b)
Sc1
Co3
Ge2
Ge3
Li
P
PP1Pk
Vel

59
Q

ANTIBODIES CAPABLE OF BINDING COMPLEMENT

(SOME)

A

Xg(a)
LKE
Lan

60
Q

ANTIBODIES CAPABLE OF BINDING COMPLEMENT

(RARE)

A

D
P(1)
Lu(a)
Lu(b)
Kell
Fy(a)
Fy(b)
Co(a)
Co(b)
Di(a)
S
S
Yt(a)

61
Q

(Anticomplement)

Presence of anticomplement activity would enhance the reactions of ________ (e.g., anti-Fya and anti-K)

A

clinically significant antibodies

62
Q

(Anticomplement)

Further degradation of membrane-bound C3b and C4b occurs by removing ____ and ____ to leave C3d and C4d firmly attached to the RBC membrane

A

C3c and C4c

63
Q

(Use of Polyspecific Versus Monospecific AHG in the IAT)

most important function of polyspecific AHG is the __________

A

detection of IgG antibodies

64
Q

(Use of Polyspecific Versus Monospecific AHG in the IAT)

associated with __________ that are not caused by clinically significant antibodies

A

unwanted positive reactions

65
Q

(Use of Polyspecific Versus Monospecific AHG in the IAT)

  • __________: compared monospecific anti-IgG with polyspecific AHG
  • concluded that some clinically significant antibodies are detected with the _________ but not with anti-IgG
  • This is especially true for _____, a complement-binding IgG antibody often associated with ___________
A
  • Petz and coworkers
  • anticomplement component of AHG
  • anti-Jka ; delayed hemolytic transfusion reactions
66
Q

(Use of Polyspecific Versus Monospecific AHG in the IAT)

_________: concluded that they would continue to use polyspecific AHG reagent for routine compatibility testing

A

Howard and associates

67
Q

(Use of Polyspecific Versus Monospecific AHG in the IAT)

  • ______:when using monospecific anti-IgG to screen for unexpected antibodies and to test for blood group compatibility, it offers reliability without interference from common and clinically insignificant IgM-complement fixing antibodies
  • numerous reports of clinically significant RBC alloantibodies that were undetectable with ________
A
  • Milam
  • monospecific anti-IgG
68
Q

(Principles of the Antiglobulin Test)

Antibody molecules and complement components are _______

A

globulins (proteins)

69
Q

(Principles of the Antiglobulin Test)

Injecting an animal with human globulin stimulates the animal to produce ________ (i.e.,AHG)

A

antibody to the foreign protein

70
Q

(Principles of the Antiglobulin Test

______ employ a variety of AHG reagents reactive with various human globulins, including anti-IgG antibody to the C3d component of human complement, and polyspecific reagents that contain both anti-IgG and anti-C3d activity

A

Serologic tests

IMMUNOHEMA OFFSEM PM (7 decks)

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