Question

1. For a well in the ELISA to turn blue, what had to have been present in it?

2. Describe two different clinical uses of an ELISA?

3. Why would using an ELISA be valuable for identifying viruses?

Answer 1

ELISA is enzyme linked immuno sorbent assay is an immunological technique used for detection of foreign antigen. Here the antigen or the foreign particle is sandwiched between the primary and the secondary antibody. The primary antibody is fixed on the surface of plate. The primary antibody is biotin labelled and the secondary antibody is generally HRP (horse radish peroxidase). When the specific antigen is bind between primary and secondary antibody, after adding substrate if immune reaction is generated the blue colour is developed. When substrate is added, it converted into coloured product. The intensity of colour produced is directly proportional to the antigen present in the sample.

ELISA can be used for detection of foreign pathogen likes viruses from various biological fluids.

ELISA is also applicable for detection of antibody present in the serum.

It is also used for detection of pregnancy.

Viruses are minor pathogen that cannot be identified microscopically. It is difficult to identify which virus is present in biological fluid because it cannot be trapped and even difficult to isolate. Virus specific antibody is immobilised on solid surface. If specific virus is present the secondary antibody will binds to give colour. Hence ELISA is most specific for a specific type of viruses. That is the reason it is widely used in identification of HIV, Zika virus and other infected viruses.