Immuunsus

Immuunsus is the Estonian term for immunity or the immune system. In medical and scientific use, it refers to the body’s defense mechanisms that detect and respond to pathogens and foreign substances, while also maintaining tolerance to self. The concept encompasses both the innate first line of defense and the adaptive immune response that creates specific, memory-based protection.

The immune system involves cells, tissues, and organs. Innate immunity provides rapid, generic responses through components such as skin, mucosal barriers, phagocytes (neutrophils, macrophages), natural killer cells, and the complement system. Adaptive immunity, driven by lymphocytes, produces specific antibodies and cytotoxic responses via B cells and T cells. Major organs include bone marrow (blood cell production), thymus (T cell maturation), lymph nodes, and the spleen.

Immuunsus develops through exposure to pathogens, vaccination, and maternal antibodies. Immunity can be humoral (antibody-mediated) or cellular (T cell–mediated); most protection involves both. Immunological memory enables faster and stronger responses upon re-exposure. Immunity can be natural or acquired, active (production of antibodies) or passive (transfer of antibodies).

Clinical relevance includes immunodeficiencies, autoimmune disorders, and allergies. Public health relies on vaccination and herd immunity to reduce pathogen transmission. Ongoing research seeks to understand immune aging, tolerance, and responses to emerging pathogens.