Unit 7: The Effects of Fixation and Processing on IHC

Immunofluorescent techniques are generally performed on ____

unfixed, frozen sections

T/F tertiary structure of protein is the most stable

true

Air-drying is followed by …

chemical fixative

T/F air-dried slides tend to give stronger IHC staining

false

T/F alcohol and acetone are non-additive

true

T/F glutaraldehyde and formaldehyde are non-additive

false

What is also known as chemical crosslinking?

additive fixation

T/F more crosslinking occurs in additive fixation than non-additive

true

Formalin reacts with __ groups that are uncharged to form addition products.

amino

What is the addition product formed by formalin?

reactive hydroxyl methyl compound

At an acid pH, amino groups are __

charged

At a basic pH, amino groups are __

uncharged

T/F If formalin reacts with amino acids within the epitope, the antibody will be unable to bind.

true

What contains formalin, picric acid, and glacial acetic acid?

Bouin solution

What is used to remove picric acid (for Bouin)?

70% alcohol

T/F mercury based fixatives are considered additive and coagulative

true

T/F non-additive fixatives could bind with the amino acid of the epitope and prevent binding of the antibody

false

What contains both mercury and potassium dichromate?

Zenker’s

T/F polyclonal antibodies are more likely to be affected by fixation than monoclonal antibodies

false

T/F vimentin is formalin sensitive

true