Types of Immunity

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

types of immunity