Question

Which of the following vaccines is made from recombinant DNA technology?
(a) FMD
(b) BCG
(c) Hepatitis
(d) Anthrax

Answer 1

Hint: Every pathogen which causes a disease has a particular identification mark which is also called an antigen. If only antigen (and not the entire pathogen) is injected into an organism, the organism develops antibodies without being infected. This antigen can be produced in large quantities using a host organism which is done using rDNA technology. This technique is a boon in making vaccines for viral infections.

Complete answer:
Hepatitis is caused by hepatitis B virus and affects the liver. Initially symptoms like vomiting, abdominal pain, yellowish skin and dark urine are observed. If left untreated the virus can cause further damage like liver cirrhosis and might also cause hepatic carcinoma. The capsid of the virus has a particular protein sequence which is called as antigen HB. The specific gene which codes for the antigenic protein is taken from the virus and ligated into a plasmid. This plasmid is called a recombinant plasmid. It is then inserted into a host like yeast which then replicates this plasmid with each cell division. Hence, in the fermentation tank, a large amount of antigen HB is produced along with yeast cells. Since this is just an antigen it cannot cause the infection but can trigger the immune system to produce antibodies. The large amount of antigen HB produced in the tank is then purified i.e. separated from yeast cells and is then used as a vaccine.
So, the correct answer is 'Hepatitis.'

Note: rDNA technology is widely used for making vaccines of most diseases caused by viruses. To make vaccines for diseases caused by bacteria, the genome of the bacterial cell is simply separated from the cell membrane and the membrane only is used as a vaccine. Another method is to make use of killed cells of bacteria. Killed cells will not cause infection but would definitely trigger the host immune system to produce antibodies.