Dendritic Cells | British Society for Immunology

Ali Roghanian, University of Southampton Faculty of Medicine, UK dendritic cells ( DCs ), named for their probe, ‘ tree-like ’ or dendritic shapes, are responsible for the knowledgeability of adaptive immune responses and hence function as the ‘ sentinels ’ of the immune system. Paul Langerhans first described DCs in human peel in 1868 but thought they were cutaneous heart cells. DCs are bone marrow  ( BM ) -derived leukocytes and are the most potent type of antigen-presenting cells. They can besides be propagated in vitro from BM and blood using versatile combinations of emergence factors, such as granulocyte macrophage-colony stimulating factor ( GM-CSF ) and Flt3 ligand. DCs are specialised to capture and work antigens, converting proteins to peptides that are presented on major histocompatibility complex ( MHC ) molecules recognised by T cells. DCs are heterogenous, e.g. myeloid and plasmacytoid DCs ; although all DCs are able of antigen uptake, processing and presentation to primitive T cells, the DC subtypes have distinct markers and disagree in localization, migratory pathways, detail immunological routine and addiction on infections or incendiary stimuli for their generation. During the development of an adaptive immune reply, the phenotype and routine of DCs play an highly significant character in initiating tolerance, memory, and polarised T-helper 1 ( Th1 ), Th2 and Th17 specialization .

DCs linking innate and adaptive immunity

Since DCs have numerous cytoplasmic processes, they have a high surface area permitting familiar contact with a bombastic count of surrounding cells, e.g. T cells, lifelike killer cells, neutrophils, epithelial cells etc. For example, experimentally, entirely one mature DC ( mDC ) is required to stimulate 100–3000 T cells. DC precursors migrate from the BM through the blood stream to about every non-lymphoid weave, where they reside in an young express ( iDC ), endlessly sampling their environment by endocytosis, macropinocytosis, and phagocytosis. They can extend their processes through the tight junctions of epithelium to increase capture of antigens even when there is no overt infection/inflammation. During pathogen invasion, resident iDCs detect intruders via convention realization sense organ ( e.g. TLRs ) capture antigens and cursorily leave the tissue. They crawl through the cells, cross the endothelium of lymphatic vessels and migrate to the draining lymph nodes ( LN ) in reaction to a number of chemokines such as CCL19 and CCL21. During their migration from the peripheral tissues, DCs undergo phenotypical and functional growth. Most signally, they stop capturing antigens while up-regulating the expression of co-stimulatory molecules such as CD80 and CD86  and the chemokine receptor CCR7, and secrete proinflammatory cytokines such as TNF- α and IL-12. After reaching the subcapsular sinus of the LN, DCs move to T-cell zones. here, the interdigitating DCs are actively involved in the presentation of antigens to T cells.

Figure 1. Dendritic cell morphology: Left: LPS-matured murine BM-derived DCs. Right: Isolated murine lung CD11c+ and MHCII+ DCs.

DC immunotherapy

Exploiting the immune-regulatory capacities of DCs holds great promise for the treatment of cancer, autoimmune diseases and the prevention of transplant rejection. handling of DCs could turn them into the most effective adjuvant to enhance the server ’ sulfur immune defences. In the case of cancer, tumours  have been shown   to suppress DCs by   secreting anti-inflammatory cytokines such as IL-10, and therefore conditioning the local DCs to form suppressive T cells. In order to subvert these mechanisms, DCs could be generated ex-wife vivo, loaded with tumor antigens, and re-injected to boost the server ’ s unsusceptibility against the tumor cells. DC vaccines generated in this way are by and large condom with minimal side effects, and have proven to be feasible, and effective in some patients. other strategies exploiting DCs in respective disorders have besides been described and are being investigated in clinical trials .
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