Langerhans cell

Source: Wikipedia, the free encyclopedia.
Not to be confused with the cells of the
islets of Langerhans in the pancreas, or Langhans giant cell
.
Langerhans cell
mucosa
FunctionDendritic cell
Identifiers
MeSHD007801
FMA63072
Anatomical terms of microanatomy]
The representation of Langerhans cells in the Cell Ontology. A portion of the Cell Ontology is shown with ovals corresponding to cell types defined in the ontology and arrows corresponding to relations between those cell types. Langerhans cell is represented by a yellow oval; blue arrows correspond to is_a relations, and orange arrows correspond to develops_from relations. Only a subset of Langerhans cell parent types are included in the figure.[1]

A Langerhans cell (LC) is a tissue-resident

papillary dermis, particularly around blood vessels,[4] as well as in the mucosa of the mouth, foreskin, and vaginal epithelium.[5] They can be found in other tissues, such as lymph nodes, particularly in association with the condition Langerhans cell histiocytosis
(LCH).

Function

In

microbial antigens to become fully functional antigen-presenting cells.[6]

Generally, tissue-resident macrophages are involved in immune homeostasis and the uptake of

naive T-cells.[medical citation needed
]

Langerhans cells derive from primitive erythro-myeloid progenitors that arise in the yolk sac outside the embryo in the first trimester of pregnancy, and under normal circumstances persist throughout life, being replenished by local proliferation as necessary. If the skin becomes severely inflamed, perhaps because of infection, blood monocytes are recruited to the affected region and differentiate into replacement LCs.[7]

dendritic cells.[9]

LCs contain a large amount of

cannabinoid receptor type 2 (CB2), that by activation by agonists, attenuate both the recruitment of eosinophils and ear swelling in chronic contact dermatitis induced by repeated challenge.[10]

Clinical significance

Langerhans cell histiocytosis

In the rare disease Langerhans cell histiocytosis (LCH), an excess of cells similar to these cells are produced. However LCH cells stain positive to CD14 which is a monocyte marker and shows a different, hematopoietic origin for the disorder.[11] LCH can cause damage to skin, bone and other organs.[citation needed]

HIV

Langerhans cells may be initial cellular targets in the sexual transmission of HIV,[12] and may be a target, reservoir, and vector of dissemination.[13] Langerhans cells have been observed in foreskin, vaginal, and oral mucosa of humans; the lower concentrations in oral mucosa suggest that it is not a likely source of HIV infection relative to foreskin and vaginal mucosa.[5]

Human papillomavirus

High-risk

human papillomaviruses (HPV) are sexually transmitted viruses causally associated with several cancers including cervical, vaginal, anal, and head and neck cancers that cause significant morbidity and mortality worldwide.[14][15][16][17] Over half of all cervical cancer cases are associated with HPV16, the most common of the cancer-causing high-risk genotypes.[18] During its natural life cycle, HPV16 infects the basal cells of the epithelium and interacts with Langerhans cells within the epithelial layer,[19] which are responsible for initiating immune responses against epithelial invading pathogens.[20] However, HPV does not activate Langerhans cells in vitro, and this may represent a key mechanism by which HPV evades immune detection in vivo.[21][22][23][24] Specifically, HPV16 entry into Langerhans cells via the annexin A2/S100A10 heterotetramer results in suppressive signaling and lack of Langerhans cell-mediated immune responses.[25] This Langerhans cell-targeted immune escape mechanism seems to be conserved among different HPV genotypes enabling these viruses to remain undetected in the absence of other inflammatory events.[26] T cells exposed to these inactivated Langerhans cells are not anergic, and can be activated against HPV upon receiving the appropriate stimuli at a later time point.[27]

It was demonstrated that Langerhans cells in HPV-induced cervical lesions were spherical, lacked dendrites, and secreted the suppressive cytokine IL-10 in vivo.[28] The authors further demonstrated that the number of IL-10 secreting immunosuppressive Langerhans cells, and the amount of IL-10 produced in lesions, corresponded with the severity of histopathology and HPV viral load, providing evidence of an active immunosuppressive mechanism employed by HPV that targets Langerhans cells in vivo.[citation needed]

Dengue fever

Langerhans cells are also the initial target of the virus that causes dengue fever during its development.[29]

Declining function during ageing

During ageing the capacity of Langerhans cells to migrate declines.[30] This compromises immunity and exposes the skin to infectious diseases and cancer.[citation needed]

History

Langerhans cells are named after

medical student.[31] Because of their dendrite-like appearance, he mistakenly identified the cells as part of the nervous system.[32]

See also

References

  1. PMID 19243617
    .
  2. PMID 28720426
    .
  3. ^ "MeSH Browser".
  4. ^
    ISBN 0-443-05612-9
    .
  5. ^
    PMID 7558138
    .
  6. S2CID 255039948
    .
  7. PMID 26554892
    .
  8. S2CID 37296843
    .
  9. PMID 18086861. Archived from the original
    (PDF) on 2018-07-19. Retrieved 2018-11-04.
  10. S2CID 11946479
    . Retrieved 2023-03-26.
  11. ^ "NCI Summary View > Urology - Yale School of Medicine". medicine.yale.edu. Archived from the original on 17 June 2019. Retrieved 19 April 2018.
  12. PMID 16226431
    .
  13. PMID 8786894
    .
  14. S2CID 1522249
    .
  15. PMID 21471563
    .
  16. PMID 23830197
    .
  17. PMID 23467841
    .
  18. PMID 7791229
    .
  19. PMID 18031245
    .
  20. S2CID 22286432
    .
  21. PMID 12218143
    .
  22. PMID 12839929
    .
  23. PMID 15905561
    .
  24. PMID 19864613
    .
  25. PMID 24719459
    .
  26. PMID 24606705
    .
  27. PMID 27182559
    .
  28. PMID 26059395
    .
  29. PMID
    19822889.
  30. PMID 28777886
    .
  31. S2CID 6282875
    .
  32. ^ Online Mendelian Inheritance in Man (OMIM): Langerhans cell histiocytosis - 604856

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Langerhans_cell&oldid=1214500708"