Immunity is the ability of the body to fight against infectious agents. The immunity can be classified as innate immunity and acquired immunity.
- Innate immunityis a non-specific type of defense mechanism. It has four types:
- i) Physical barrier: Example, skin covering of the body, secretion of mucous in the respiratory tract
ii)Physiological barrier: Example, acid in the stomach, tears from the eyes
iii) Cellular barrier: Example, monocytes and lymphocytes in blood
- Cytokine barrier: Example, interferon
- Acquired immunity:it is a specific type of defence mechanism. It shows two types of responses: primary response and secondary response. It involves two types of lymphocytes –
- B lymphocytes: Show humoral immune response (HI)
- T lymphocytes: Show cell mediated immunity (CMI)
