Question

Expand ELISA. On what principle is ELISA test based? List two ways by which an infection can be detected by this test.

Answer 1

The enzyme-linked immunosorbent assay (ELISA) is commonly used analytical biochemistry assay which was described by Perlmann and Engvall in 1971.The assay uses a solid-phase type of enzyme immunoassay to detect presence of ligand in liquid sample using antibodies directed against the protein.

Complete answer:
ELISA is enzyme-linked immunosorbent assay which is used in analytical biochemistry assay and helps in detection of diseases. The principle on which the ELISA is based is that specific antibodies bind to the target antigen as it is based on the principle of antibody-antigen interactions. When the interaction occurs the substrate will be able to bind to the enzyme and substrate conversion can be witnessed which give a positive result.
There are two ways by which the interaction can be detected by these methods and these ways are listed below:
1.Sandwich ELISA: This is in which the sample is sandwiched between two layers of antibodies and if the interaction occurs a substrate reaction will be witnessed in addition of a conjugated antibody and substrate. This method help in detection of rotavirus and HIV in the body.
2.Direct ELISA: I this the sample is first added and secondly the enzyme-conjugated antibody is added. If any interaction takes place then reaction will be seen on substrate addition.

Note: ELISA plays a vital role in detection of certain diseases which are otherwise not detectable. This helps to figure out the presence of some viruses which are dangerous for our body and help us to cure it at an early stage.