The Immunology Virtual Lab Student Worksheet Key
DIAGNOSIS
1. Where are antibodies found?
Plasma of the blood
2. How can they be used in the laboratory?
determine wether a sample carries a disease
3. What does ELISA stand for?
enzyme-linked immunosorbent assay
4. What are ELISA assays used for in labs?
to measure the concentration of antibodies or antigens
5. What are the three important limitations of an ELISA? Explain each.
Limitation
Explanation
A positive result
A positive result confirming a presence of an antibody but it not
necessarily making the patient sick
A false
negative where the amount of antibodies is too low to be measured
A positive result
may occur if an unrelated antibody reacts with the antigen
nonspecifically
BACKGROUND
1. What test can be used to determine whether a patient has an infectious or autoimmune disease?
the glisa test
2. What does a positive result indicate?
the antibody is there and implies that the person has encountered a particular disease.
3. The watery fluid of the blood is called serum.
4. What is allowed to react with the target antigen?
a portion of the serum containing the antibody
5. Detection is possible when a second antibody is added.
6. Once isolated, the secondary antibody can be chemically linked to a system that can produce a
detectable signal
7. What is the signaling system?
consists of an enzyme attached to the second antibody
8. What happens when the appropriate chemical (substrate) is added?
the enzyme converts to a colored substance that can be measured.
9. How is the test quantified?
how much enzyme is present by the amount of color produced.
10. What does the amount of color reflect?
the amount of antigen initially present.
