Autoimmunity

Immunity refers to the resistance exhibited by the host towards the injury caused by micro-organisms and their products. Protection against infectious diseases is the only consequence of the immune response, which is directly concerned with the reaction of the body against any foreign antigen. Autoimmunity is when the body's natural defence mistakenly attacks the body's own tissue. It is present in humans to some extent. It is usually harmless and probably a universal phenomenon for human life. The immune mechanism differs from one autoimmune disease to another. Nowadays it is accepted that autoimmune responses are an integral part of vertebrate immune systems.

Immunity refers to the body's ability to resist injury caused by microorganisms and their products, and can be categorized into innate and acquired types. Innate immunity is present by default, while acquired immunity develops throughout life, either actively through antigen exposure or passively via the transfer of pre-formed antibodies. Active immunity is long-lasting and provides immunological memory, whereas passive immunity offers immediate but temporary protection. The concept of autoimmunity is also discussed, where the immune system mistakenly targets the body’s own cells, leading to autoimmune diseases. The text provides a foundational understanding of immune mechanisms and their role in health and disease.

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