Immunity

Description

Immunity is the body's ability to recognise and defend against harmful substances and pathogens. It is broadly classified into innate and adaptive types. Innate immunity offers immediate, nonspecific defense using barriers, phagocytes, and inflammatory responses. Adaptive immunity is specific, slower to respond, and involves B cells (producing antibodies) and T cells (cell-mediated defense). Immunity can be active (developed after infection or vaccination) or passive (antibody transfer). Together, these systems protect the body, promote healing, and provide long-term resistance to disease.