Immunity can be described as either active or passive, depending on how it is acquired:
- Active immunity involves the production of antibodies by the body itself and the subsequent development of memory cells
- Passive immunity results from the acquisition of antibodies from another source and hence memory cells are not developed
Active immunity will result in long-term immunity but passive immunity will not (due to the presence or absence of memory cells)
- Both active and passive immunity can be induced by either natural or artificial mechanisms
Examples of Active Immunity
- Natural – Producing antibodies in response to exposure to a pathogenic infection (i.e. challenge and response)
- Artificial – Producing antibodies in response to the controlled exposure to an attenuated pathogen (i.e. vaccination)
Examples of Passive Immunity
- Natural – Receiving antibodies from another organism (e.g. to the foetus via the colostrum or a newborn via breast milk)
- Artificial – Receiving manufactured antibodies via external delivery (e.g blood transfusions of monoclonal antibodies)
Types of Immunity
