Immune reactions

“Immune reactions” refer broadly to the coordinated cellular and molecular events initiated when the body detects foreign substances (antigens), including pathogens like bacteria and viruses. These responses involve both innate immunity—which provides immediate but non-specific defense through cells such as phagocytes and natural killer cells—and adaptive immunity—which mounts targeted attacks via T cells and B cells producing antibodies[1][3][4]. The process includes recognition via pattern-recognition receptors (PRRs) such as Toll-like receptors on innate cells[3][9], activation cascades involving cytokines like interleukins[2], antibody production by B lymphocytes[2], direct cytotoxicity by T lymphocytes[4], inflammatory mediator release leading to tissue changes[4], memory cell formation for faster future responses[1], and regulation through feedback mechanisms. Dysregulation can result in autoimmunity or chronic inflammation; insufficient activity leads to increased infection risk; excessive activity may cause tissue damage. Because “immune reaction” encompasses many distinct molecules, pathways, cell types, mediators (e.g., cytokines), it should not be used where specificity about drug targets is required.

Other names

Immune responseImmunological reactionHost defense response