Immunological Testing

Question 1

What does ELISA stand for?
What do ELISA tests measure for?
What are the advantages of ELISA tests?

Answer 1

Enzyme-linked Immunosorbent Assay
Measures Ag or Ab, in infection or hypersensitivity
Quantifiable, Quick, Reproducible, Inexpensive

Question 2

What does more colour in an ELISA test mean?

Answer 2

More antibody or antigen

Question 3

What is end point titration?

Answer 3

Taking a single sample from serum that doesn’t show concentration
Two different concentrations cans show the same results
In end point titration solutions are diluted- 1/2, 1/4, 1/8 etc until the antibody is shown to be no longer present
This is because there is a limit to binding in an ELISA tes- they become saturated

Question 4

How can immune complex formation visuals antibody antigen reactions?

Answer 4

Formed by antibody binding antigen
Can be large/small deepening on amounts of ag/ab and the class of antibody
Immune complex may appear as precipitate and be visible

Question 5

What agglutination reactions can show bacterial infections?

Answer 5

Antibodies from animals can test for bacteria- agglutinate and can be seen
RBC coated with antigen and mixed with test sera- +ve sera causes agglutination

Question 6

How do SNAP tests work?

Answer 6

Add drop of patients serum potentially containing ab
Gold particles with protein bind and form complex
Complex migrates up paper to specific antigen, if specific antibody present it forms complex an a line appears
Another line shows its a successful test

Question 7

What is the disadvantage of immunofluorescent detection?

Answer 7

Some tests cannot be done due to lack of fluorescence reader/microscope

Question 8

What is a virus neutralisation test?

Answer 8

Anti-viral antibodies stop viral growth in vitro, reduce cytopathic effect of virus in culture
Titre serum to measure antibody level

Question 9

What is a haemagglutination inhibition test?

Answer 9

Some viruses agglutinate RBC

Antibodies to virus will block agglutination

Question 10

How can T lymphocyte function be used for testing for disease?

Answer 10

Testing the recruitment of T-memory cells
Antigen presenting cell is tested against serum
If animal exposed to disease the T cells release IFN gamma- ELISA measures amount of IFN gamma
TB testing