Q.15 Describe the mode of action of vaccines?
Answer:
Antigens
Pathogens contain special proteins called antigens.
Antibodies
When pathogens enter the body (blood) of host, these proteins stimulate the immune response in host i.e. synthesis of antibodies. Antibodies bind to pathogens and destroy them.
Memory cells
These cells are produced which remain in blood and provide protection against future infections with the same pathogen.
Action of vaccine / Working of Vaccineย
When a vaccine i.e. weakened or dead pathogen is introduced into bloodstream, the white blood cells are stimulated; B-Lymphocytes recognize the weakened or dead pathogens as enemies and start producing antibodies against them. These antibiotics remain in blood and provide protection against pathogens. If real pathogens enter blood, the already present antibodies kill them.
