Lesson 8 – Enzyme Linked Immunosorbant Assay exam

1. An anti-antibody is an antibody directed against which of the
following?

a) An antigen found on normal body cells

b) A large and complex antigen

c) Another antibody molecule

d) Two or more different antigens

2. Which of the following does NOT describe advantages of ELISA tests?

a) They can detect either antigens or antibodies

b) They can quantify the amounts of antigen or antibody in a sample

c) They can be easily automated

d) They can demonstrate the presence of multiple antigens

3. Place the following five steps of ELISA in the correct order. 1. Add
sample serum to each well. 2. Enzyme substrate is added to each well.
3. Anti-antibodies with enzyme are added to each well. 4. Each well is
coated with antigen molecules in solution. 5. Excess antigen is washed
and gelatin is used to coat any surface not coated with antigen.

a) 1,2,3,5,4

b) 4,5,1,3,2

c) 5,4,3,2,1

d) 4,5,2,1,2

4. Direct ELISA is a method in which ______?

a) The antigen is bound nonspecifically to the wells of a polystyrene plate.

b) wells are first coated with a specific antibody to capture only the specific antigen from the test sample

c) An unlabeled primary antibody is incubated with the captured antigen

d) All of these

5. The substrate of horse radish peroxidase is

a) p-nitro phenyl phosphate

b) 4-methylumbelliferyl phosphate

c) 5-tetramethyl benzidine

d) None of the above

6. The indirect ELISA requires known

a) Antigen

b) Antibody

c) Enzyme

d) Serum

7. Which of the following is immobilized on the microtiter well in
sandwich ELISA?

a) Detection antibody

b) Sample

c) Capture antibody

d) Secondary antibody conjugated to an enzyme

8. What does a weak color signal in competitive ELISA represent?

a) More antigen in the sample

b) Less antigen in the sample

c) Less antigen retained on the well

d) Both ‘a’ and ‘c’

9. ELISA (enzyme-linked immunosorbent assay) allows for rapid
screening and quantification of the presence of _______ in a sample.

a) Antigen y

b) Antibod

c) Protein

d) DNA

10. In an enzyme immunoassay, the enzyme

a) Bound by the antibody’s antigenbinding site.

b) Conjugated to the suspect antigen.

c) Attached to the well of a microtiter plate.

d) Bound to the constant region of the secondary antibody.

11. The most commonly used serological test ELISA was developed by
and .

12. To detect antibodies against bacteria in the bloodstream, always run an
, which would start by attaching antigen from the bacteria
to the wells of a microtiter plate.

13. ELISA tests are a diagnostic tool to determine the presence of
in blood by using known .

14. requires two antibodies specific for different epitopes of
the antigen.

15. The indirect ELISA is most suitable for determining
concentration in samples.

16. effect is caused by very high levels of antigen in the
sample.

17. as a blocking agent to prevent non-specific
binding of antigens and antibodies to the microtiter well.

18. The commonly used enzymes for labeling antibodies are
and .

19. The commonly used substrate for the Alkaline phosphatase labeled
antibody is .

20. Para-nitrophenylphosphate

21. Cross-reactivity

22. Assay sensitivity

23. Hook effect

24. Direct ELISA

25. Indirect ELISA

26. Sandwich ELISA

27. Competition/inhibition ELISA

28. Horseradish peroxidase (HRP)

29. Edge effect

30. List out the principles for different types of ELISA and their applications.

31. ELISA can be used to test for antibodies that recognize an antigen.

A) True

B) False

32. ELISA is designed for detecting and quantifying substances such as peptides, proteins, antibodies and hormones.

A) True

B) False

33. Sandwich ELISA typically requires the use of unmatched antibody pairs. .

A) True

B) False

34. Enzyme-linked immunosorbent assay (ELISA) is a plate-based assay technique designed for detecting and quantifying peptides, proteins, antibodies and hormones.

. A) True

B) False

35. Direct ELISA is a technique for direct detection of, an antigen coated to a multi-well plate, which is detected by an anti-antibody that has been directly conjugated to an enzyme. .

A) True

B) False

36. Immunoreactivity of the primary antibody might be adversely affected by labeling with enzymes or tags. .

A) True

B) False

37. Labeling primary antibodies for each specific ELISA system is not timeconsuming and cheap. .

A) True

B) False

38. Immunoassays involve tests using antibodies as reagents. .

A) True

B) False

39. Antiglobulins are produced when proteins from one species are injected into same species. .

A) True

B) False

40. Enzyme conjugate is an enzyme that is attached reversibly to a protein, usually an antibody. .

A) True

B) False

41. Chromophore is a chemical that alters color as a result of an enzyme interaction with substrate. .

A) True

B) False

42. ELISA and Cell-Based Assay Sample Analysis –Applications.

43. Describe the standard operating procedure for various components
of ELISA such as
 Preparation of sample and buffer
 Antibodies for ELISA
 Control for ELISA
 Microplate
 Microplate reader and
 Interpretation of results