Examples of mast cells in the following topics:
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- Exercise or temperature (either hot or cold) may also trigger anaphylaxis by causing tissue cells known as mast cells to release chemicals that start the allergic reaction.
- People who have disorders caused by too many mast cells in their tissues (mastocytosis) or who are wealthier are at increased risk.
- It results from the release of inflammatory mediators and cytokines from mast cells and basophils.
- The combination of IgE bound to the antigen activates FcεRI receptors on mast cells and basophils.
- The mast cells and basophils react by releasing inflammatory mediators such as histamine.
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- Immunology is the study of molecules, cells, and organs that make up the immune system.
- When a foreign agent penetrates the first line of resistance, an immune reaction is elicited and immune cells are recruited into the site of infection to clear microorganisms and damaged cells by phagocytosis.
- If the inflammation remains aggravated, antibody-mediated immune reaction is activated and different types of immune cells are engaged to resolve the disease.
- The cellular component includes mast cells, neutrophils, macrophages, T and B lymphocytes, and plasma cells.
- Because antibodies can be produced against any type of macromolecule, antibody-based techniques are useful in identifying molecules in solution or in cells.
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- The thymus "educates" T cells and provides an inductive environment for the development of T cells from hematopoietic progenitor cells.
- The innate leukocytes include the phagocytes, mast cells, eosinophils, basophils, and natural killer cells.
- Mast cells reside in connective tissues and mucous membranes, and regulate the inflammatory response.
- Natural killer cells are leukocytes that attack and destroy tumor cells, or cells that have been infected by viruses.
- B cells and T cells are the major types of lymphocytes and are derived from hematopoietic stem cells in the bone marrow.
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- Red blood cells carrying CR1-receptors on their surface may bind C3b-decorated immune complexes and transport them to phagocytes, mostly in liver and spleen, and return back to the general circulation.
- Activation of complement primarily results in cleavage of soluble complement proteins forming C5a and C3a, which activate recruitment of PMNs and local mast cell degranulation (requiring the binding of the immune complex onto FcγRIII), resulting in an inflammatory response.
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- The complement system helps or "complements" the ability of antibodies and phagocytic cells to clear pathogens from an organism.
- The following are the basic functions of the complement: opsonization (enhancing phagocytosis of antigens); chemotaxis (attracting macrophages and neutrophils); cell lysis (rupturing membranes of foreign cells); and clumping (antigen-bearing agents).
- C5a is an important chemotactic protein, helping recruit inflammatory cells.
- Both C3a and C5a have anaphylatoxin activity, directly triggering degranulation of mast cells, as well as increasing vascular permeability and smooth muscle contraction.
- Kupffer cells and other macrophage cell types help clear complement-coated pathogens.
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- It is characterized by solvent antigens that are not bound to cell surfaces (which is the case in type II hypersensitivity).
- The cause of damage is as a result of the action of cleaved complement anaphylotoxins C3a and C5a, which, respectively, mediate the induction of granule release from mast cells (from which histamine can cause urticaria), and recruitment of inflammatory cells into the tissue (mainly those with lysosomal action, leading to tissue damage through frustrated phagocytosis by polymorphonuclear neutrophils and macrophages).
- Red blood cells carrying CR1-receptors on their surface may bind C3b-decorated immune complexes and transport them to phagocytes, mostly in liver and spleen, and return back to the general circulation.
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- Dendritic cells are immune cells that function to process antigens and present them to T cells.
- Immature dendritic cells (e.g.
- Mature dendritic cells reside in the T cell zones of the lymph nodes, and in this location they display antigens to T cells.
- Dendritic cells are constantly in communication with other cells in the body.
- This communication can take the form of direct cell-to-cell contact based on the interaction of cell-surface proteins.
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- T cells play a central role in cell-mediated immune response through the use of the surface T cell receptor to recognize peptide antigens.
- T cells do not produce antibody molecules.
- Effector cells include helper T cells, and cytolytic or cytotoxic T cells.
- Another class of T cells called regulatory T cells function to inhibit immune response and resolve inflammation.
- T cells promote the killing of cells that have ingested microorganisms and present foreign antigens on their surface.
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- Natural killer cells (or NK cells) are a type of cytotoxic lymphocyte critical to the innate immune system.
- Natural killer cells (or NK cells) are a type of cytotoxic lymphocyte critical to the innate immune system.
- The role NK cells play is similar to that of cytotoxic T cells in the vertebrate adaptive immune response.
- Often NKT cell activity promotes NK cell activity by secreting IFNγ.
- Functions of NK cells include: Cytolytic Granule Mediated Cell Apoptosis; Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC); Cytokine induced NK and CTL activation; Missing 'self' hypothesis; Tumor cell surveillance; NK cell function in adaptive response; NK cell function in pregnancy; and NK cell evasion by tumor cells .
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- Regulatory T cells are a subset of T cells which modulate the immune system and keep immune reactions in check.
- Regulatory T cells are a component of the immune system that suppress immune responses of other cells.
- These cells are also called CD4+CD25+ regulatory T cells, or Tregs.
- Additional suppressor T cell populations include Tr1, Th3, CD8+CD28-, and Qa-1 restricted T cells.
- Induced Regulatory T (iTreg) cells (CD4+CD25+Foxp3+) are suppressive cells involved in tolerance. iTreg cells have been shown to suppress T cell proliferation and experimental autoimmune diseases. iTreg cells develop from mature CD4+ conventional T cells outside of the thymus: a defining distinction between natural regulatory T (nTreg) cells and iTreg cells.