Question

You are analyzing suspect imported food for meat from turtles that have been put on the endangered species list using the ELISA test. In this test, samples containing illegal turtle meat appear blue after performing the assay.

A. If a meat sample appears clear in an ELISA test, what does this result indicate?

B. What is the purpose of using antibodies in the ELISA test?

C. In the last step of performing the test, should the enzyme or the antigen or the substrate be added to the wells? Explain (briefly) your answer.

Answer 1

A. If meat sample appears clear in an ELISA means that there no contamination in meat.It is safe to consume.

B. The antibodies is used to capture the antigens such as viruses which is causing infections.

C.In the last step of the ELISA test, the substrate is added to the well which causes the conversion of enzyme into colored product. The formation of the colored product is directly proportional to the amount of antigen present in the meat sample.

For better understanding-

ELISA includes 5 step procedure -

a.The capture antibody is coated on the surface of well and adding of blocking solution for non-specific binding.

b.Then, suspected antigenic sample (meat) is added to the well,which binds with the capture antibody.

c.Further, the detection antibody is added to the well and forms the complex of  capture antibody-meat-detection antibody

d.After that, the enzyme linked secondary antibody is added.

e.In last step, the substrate is added to react with the enzyme and produces colored products ,used for visual interpretations.

If production of coloured product occurs it means antigenic particles are present - Positive ELISA

If sample appears white,it means there is no antigenic particles are present - Negative ELISA.