Question

Describe the principle behind vaccination.

Answer 1

To produce an immune response, live attenuated vaccines must replicate (grow) in the vaccinated person. A relatively small dose of virus or bacteria is administered, which replicates in the body and creates enough of the organism to stimulate an immune response.

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Answer 2

Vaccination provides memory to the immune system of the body against particular pathogen. Vaccine is an antigenic protein, inactivated or weakened live pathogen. On introduction of the body it produces antibodies and memory B cells and memory T cells. Whenever, the pathogen attacks a vaccinated person, the memory cells induce production of lymphocytes and antibodies that overwhelm and destroy the same. Hepatitis B vaccine is produced in yeast.  

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