- Innate immunity (inherited immunity or hereditary resistance) is an inborn genetic gift.
- Acquired immunity is gained in life.
- It can be natural or artificial.
- The former develops as a defense against natural infections or antigens, whereas the latter develops in response to artificially administered vaccines, allergens etc.
- Active immunity is the resistance developed against natural or artificial antigenic stimulation.
- The immunity developed by an organism, due to the formation of antibodies from its own cells is called active immunity.
- Active immunity is produced by two ways,
- By direct attack of pathogens (mumps and measles)
- By vaccination (vaccine for polio)
- Active immunity involves the active functioning of the immune system.
- Active immunity can provide effective long-term protection.
- Passive immunity is the ready-made resistance, passively transferred to a recipient.
- Passive immunity occurs when an individual receives antibodies instead of making their own.
- Passive immunity is short-lived because the person’s B and T cells have not been stimulated to produce antibodies.
- The immunity lasts only as long as the antibodies they received remain in their bloodstream.
- Newborn babies have antibodies they received from their mother.
- Vaccines are preparations of inactivated or killed microorganisms or their products.
- The administration of vaccines to recipients is called vaccination.
- The production of active immunity through vaccination is called active immunization.
- Vaccines do not normally cause disease, because they contain only inactivated or dead antigens.
- At the same time they can trigger the functioning of the immune system and stimulate the production of antibodies
- Sometimes two or more doses are required to develop sufficient immunity against some diseases.
- In such cases the first dose is called trigger dose and the additional doses are called booster doses.