Immunohistochemistry

Question 1

List some methods of protein detection.

Answer 1

1 - ELISA
2 - Western Blot
3 - Gel electrophoresis 
4 - Specific Enzyme Assays
5 - Immunohistochemistry

Question 2

How good is the ELISA method?

Answer 2

Quantitative but no localisation

Question 3

How good is the Western Blot method?

Answer 3

used in a relative semi-quantitative manner, no possibility to locate the protein

Question 4

What does specific enzyme assays involve?

Answer 4

exploit the activity of the enzyme to process a substrate and detect the product.

Question 5

Explain the principles of immunohistochemistry.

Answer 5

often used as a complimentary technique in histology to confirm or exclude the presence of a specific protein. used when morphological information is insufficient to provide a diagnosis

IHC relies on the specific nature of antibody antigen interactions

Question 6

What information is retrieved from IHC?

Answer 6

Provides an assessment of antigen expression on the cell surface, or in cytoplasm or nucleus. IHC can localise the protein and this can be observed under the light microscope.

Question 7

How is IHC used in histopathology?

Answer 7

• defining the cell types that form a tumour
• defining which cell types are present in an inflammatory cell infiltrate
• detecting immune complex deposition in Al disorders
• providing indicators for potential target therapies
• detecting viruses that cannot be easily cultured or identified

Question 8

What is antigen retrieval?

Answer 8

aims to recover lost immunoreactivity by restoring the accessibility of the antigens to antibodies.

Question 9

What are the 2 main types of antigen retrieval?

Answer 9

1 - proteolytic enzymes to cleave cross-links

2 - heat eg microwave, water bath, pressure cooker