Cell-mediated immunity

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Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of macrophages, natural killer cells (NK), antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. Historically, the immune system was separated into two branches: humoral immunity, for which the protective function of immunization could be found in the humor (cell-free bodily fluid or serum) and cellular immunity, for which the protective function of immunization was associated with cells.

Cellular immunity protects the body by:

1. activating antigen-specific cytotoxic T-lymphocytes that are able to induce apoptosis in body cells displaying epitopes of foreign antigen on their surface, such as virus-infected cells, cells with intracellular bacteria, and cancer cells displaying tumor antigens;
2. activating macrophages and natural killer cells, enabling them to destroy intracellular pathogens; and
3. stimulating cells to secrete a variety of cytokines that influence the function of other cells involved in adaptive immune responses and innate immune responses.

Cell-mediated immunity is directed primarily at microbes that survive in phagocytes and microbes that infect non-phagocytic cells. It is most effective in removing virus-infected cells, but also participates in defending against fungi, protozoans, cancers, and intracellular bacteria. It also plays a major role in transplant rejection.

[edit] See also

• Delayed-Type Hypersensitivity

v • d • e Blood
General	Plasma - Hematopoietic stem cells
Lymphoid - WBC	T cells: Cytotoxic CD8+, Helper CD4+/Regulatory, γδ, Natural Killer T cell B cells: Plasma, Memory Natural killer cells (Lymphokine-activated killer cell)
Myeloid - WBC	Granulocytes (Neutrophil, Eosinophil, Basophil) - Mast cell precursors Dendritic cells (Langerhans cells, Follicular dendritic cells) Monocytes/Macrophages (Histiocytes, Kupffer cells, Langhans giant cells, Microglia, Osteoclasts) Megakaryoblast - Megakaryocyte - Platelets
Myeloid - RBC	Reticulocyte - Normoblast

v • d • e Immune system / Immunology
Systems	Adaptive immune system vs. Innate immune system • Humoral immune system vs. Cellular immune system • Complement system (Anaphylatoxins)
Antibodies and antigens	Antibody (Monoclonal antibodies, Polyclonal antibodies, Autoantibody) • Allotype • Isotype • Idiotype • Antigen (Superantigen)
Immune cells	White blood cells (T cell, B cell, NK cell, Mast cell, Basophil, Eosinophil) • Phagocyte (Neutrophil, Macrophage, Dendritic cell) • Antigen-presenting cell • Reticuloendothelial system
Immunity vs. tolerance	Immunity • Autoimmunity • Allergy • Tolerance (Central) • Immunodeficiency
Immunogenetics	Somatic hypermutation • V(D)J recombination • Immunoglobulin class switching • MHC / HLA
Other	Cytokines • Inflammation • Opsonin  • Cytolysin

es:Inmunidad celular

id:Kekebalan selular it:Immunità cellulare pl:Odpowiedź odpornościowa komórkowa sv:Cell-medierad immunitet