Class 12 NEET Biology Biotechnology and Its Applications

Option (4) is the correct answer as genetically engineered lymphocyctes are not immortal cells and die after some time.
Option (3) is not the correct answer as the lymphocytes from patient’s blood are grown in culture,outside the body but it is not the correct reason.
In option (2), if the gene isolated from bone marrow cells producing ADA is introduced into cells at early embryonic stages, it could be a permanent cure.