Immunohistochemistry Flashcards

1
Q

Define ‘immunohistochemistry’.

A

Any method using labelled antibodies to detect a specific antigen

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2
Q

_________ antibodies, which are sera, containing multiple antibodies to the antigenic epitopes.

A

Polyclonal

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3
Q

List four characteristics of polyclonal antibodies.

A

Many different species are involved
Tend to have more non-specific reactivity
Can have wildly different affinity or avidity from batch to batch
More likely to have success in uncertain applications

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4
Q

What is a monoclonal antibody?

A

Antibody-producing cells that are harvested from the spleen of the animal, fused with tumour cells, and grown in cell culture (hybridoma technology)

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5
Q

True or false: monoclonal antibodies are less likely to get false negative results.

A

False

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6
Q

Antibody attaches to the cell/tissue antigen, and is then visualised with a __________ through a label.

A

Chromagen

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7
Q

________ can be intra- or extracellular, membranous, nuclear components, etc..

A

Antigens

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8
Q

List three features of IHC which must be considered when choosing reagents.

A

Controls
Direct vs. indirect methods
Fluorescence
Multiple labelling characteristics

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9
Q

What are primary antibodies?

A

Usually monoclonal antibodies which detect and bind to specific epitope(s) of antigen which is usually a cell surface antigen, e.g., mouse antihuman macrophage

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10
Q

What are secondary antibodies?

A

Antibodies that bind to primary antibodies or antibody fragments

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11
Q

True or false: secondary antibodies are usually labelled.

A

True

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12
Q

Secondary antibodies bind to the primary antibody only, and not to the ______ ________ _______.

A

Cell surface antigen

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13
Q

___________ methods employ primary antibodies only.

A

Direct

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14
Q

What do indirect antibodies employ?

A

Primary and secondary antibodies

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15
Q

True or false: enzymatic methods are direct.

A

False

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16
Q

Name a popular enzymatic method.

A

PAP method

17
Q

Applying layers of antibodies (primary, secondary and maybe tertiary) and labels is more _____________ for antigen detection.

18
Q

What is one disadvantage of direct methods?

A

They are expensive

19
Q

Describe the avidin-biotin-enzyme complex.

A

An indirect, three-step method, whereby the primary antibody unlabelled, and secondary antibody is biotin-labelled. The third layer is an avidin-enzyme complex. Avidin and biotin have very high affinity for one another. The enzyme conjugate catalyses a reaction with a substrate (chromogen), which changes colour

20
Q

What method of detection does the EnVision FLEX exploit?

21
Q

Describe the polymer method of detection.

A

The primary antibody is unlabelled, and the second layer is a dextran polymer of multiple antibodies and labels

22
Q

Localising the antigen-antibody complex in IHC relies on _______, which are very readily attached to antibodies.

23
Q

Labels may be radioactive isotopes, enzymes, ________, metals, and fluorescent dyes.

24
Q

In cells and _________, the label is used to create a colour at the site of staining.

25
List two fluorescent dyes.
Rhodamine and fluorescein IsoThioCyanate FITC
26
____________ dyes include peroxidase and glucose oxidase.
Enzymatic
27
________ ____________ uses an Azo dye reaction to visualise a red colour.
Alkaline phosphatase
28
With _________________, oestrogen receptor-positive breast tumour cells can be identified by brown stain.
Immunoperoxidase
29
What is the principle of the DAB reaction?
The DAB reaction uses peroxidase, which is attached at site of antigen during IHC reactions. Peroxidase then acts on a hydrogen peroxide substrate to release oxygen, which causes a brown polymer of diaminobenzidene to form
30
True or false: IHC is an adjunct to tissue morphology and used in addition to the H&E.
True
31
List four reasons why IHC testing would be requested.
Confirmation of tumour type suspected on H&E Identification of adjacent tumour spread Identification of distant metastases Identification of tumours of unknow etiology
32
A panel of antibodies is used in IHC to different _____ _______ _________, which are present on tumour cell.
Cell type antigens
33
____________ is present on epithelial tumours; antibody names include MNF116, AE1/AE3, and PanCytokeratin.
Cytokeratin
34
Expression of antigens/proteins in the _______ ______ is predictive of response to therapy, and/or more aggressive tumours.
Tumour cells
35
For breast cancer, oestrogen and progesterone receptors are responsive to oestrogen blocking with ____________.
Tamoxifen