VMC 221: Veterinary Immunology and Serology (1+1)

TYPES OF ADAPTIVE IMMUNE RESPONSE

• There are two types of adaptive immune responses:
  • Humoral immunity: Produced by B-lymphocytes and mediated by the production of antibodies, which neutralize the target microbes and eliminates from the body by several effector mechanisms.
  • Cellular immunity: Produced by T- lymphocytes and mediated by production of effector cytokines which activate macrophages to kill microbes residing in phagocytes and cytotoxic T cells  kill the infected cell to eliminate infection.
• Adaptive immunity can be acquired by two ways
  • Active immunity
  • Passive immunity.

• Active immunity: When the host’s body in response to foreign antigen produces antibody, the immunity develops slowly and persists for a long time. Active immunity may be
  • Natural: When produced due to natural infection by infectious organisms.
  • Artificial: This is produced by the host’s body in response to inoculation of an antigen e.g., vaccination
• Passive immunity : The antibody is prepared elsewhere and subsequently introduced into host’s body. The immunity is rapidly established but persists for short duration. Passive immunity may be of two types
  • Natural
    • Maternal antibody from mother to foetus (Tran placental transfer)
    • Colostrum antibody through milk from mother to neonates.
  • Artificial
    • By injection of immune serum in case of tetanus
    • Transfer of lymphocyte or immune cells.