(a) (i) Give the full form of 'ELISA'. Write the principle on which ELISA test is based. (ii) Describe all the methods used to treat or cure…

• ELISA: Enzyme Linked Immuno Sorbent Assay

• Principle: Antigen – Antibody interaction

− (ii) − Bone marrow transplantation from a healthy donor.

− Enzyme replacement therapy, is when functional ADA is given to the patient by injection.

− Gene therapy, lymphocytes from the blood of the patient are grown in a culture outside the body, A functional ADA cDNA (using a retrovirus) is then introduced into these lymphocytes which are subsequently returned to the patient.

− If the gene isolated from marrow cells producing ADA is introduced into cells at early embryonic stages it could be a permanent cure.

− DNA fragments are negatively charged molecules, they can be separated by forcing them to move towards the anode, under an electric field, through a medium or matrix of agarose gel, the fragments separate according to their size, the smaller fragments will move farther, fragments are stained with ethidium bromide, and viewed under UV light and are seen as bright orange bands.

− The separated band of DNA are cut out from the gel, DNA is extracted from the gel by elution.