Langerhans cell
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Langerhans_cell".

Langerhans' cells are dendritic cells abundant in epidermis, containing large granules called Birbeck granules. They are normally present in lymph nodes, and can be found in other organs in the condition Histiocytosis.

Section of skin showing large numbers of dendritic (Langerhans cells) in the epidermis. (M. ulcerans infection, S100 immunoperoxidase stain.)
Section of skin showing large numbers of dendritic (Langerhans cells) in the epidermis. (M. ulcerans infection, S100 immunoperoxidase stain.)

Specifically, the Langerhans cells are located primarily in the stratum spinosum portion of the epidermis.

Named after German anatomist and physician Paul Langerhans (1847-1888) who described it in skin when he was a medical student.

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Function

On infection of an area of skin, the local Langerhans' cells will take up and process microbial antigens to become fully-functional antigen-presenting cells.

Generally, dendritic cells in tissue are active in the capture, uptake and processing of antigens. Once dendritic cells arrive in secondary lymphoid tissue however, they lose these properties while gaining the capacity to interact with naive T-cells.

Langerhans' cells are derived from the cellular differentiation of monocytes with the marker "Gr-1" (also known as "Ly-6c/G"). The differentiation requires stimulation by colony stimulating factor-1.[1] They are similar in morphology and function to macrophages. [2]

Clinical significance

LCH

In the rare disease Langerhans' cell histiocytosis (LCH), an excess of these cells is produced, which can cause damage to skin, bone and other organs.

HIV

Langerhans' cells capture HIV-1 virions by way of Fc receptor binding to antibody-coated virus. Langerhans' cells act as reservoirs for the HIV-1 virus, serving as a site of replication when T-cells become depleted (Robbins Pathology).

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.[3]

On March 4, 2007 the online Nature Medicine magazine published the letter "Langerin is a natural barrier to HIV-1 transmission by Langerhans cells."[4] Teunis Geijtenbeek, one of the authors of the study, said that "Langerin is able to scavenge viruses from the surrounding environment, thereby preventing infection" and "since generally all tissues on the outside of our bodies have Langerhans cells, we think that the human body is equipped with an antiviral defense mechanism, destroying incoming viruses."[5]

See also

References

  1. ^ Ginhoux F, Tacke F, Angeli V, Bogunovic M, Loubeau M, Dai X, Stanley E, Randolph G, Merad M (2006). "Langerhans cells arise from monocytes in vivo". Nat Immunol 7 (3): 265–73. doi:10.1038/ni1307. PMID 16444257. 
  2. ^ Semester 4 medical lectures at Uppsala University 2008 by Leif Jansson
  3. ^ Hussain, LA, Lehner T (1995). "Comparative Investigation of Langerhans' cells and Potential Receptors for HIV in Oral, Genitourinary and Rectal Epithelia". Immunology 85: 475–484. PMID 7558138. 
  4. ^ de Witte L, Nabatov A, Pion M, Fluitsma D, de Jong M, de Gruijl T, Piguet V, van Kooyk Y, Geijtenbeek T (2007). "Langerin is a natural barrier to HIV-1 transmission by Langerhans cells". Nat Med 13 (3): 367–71. doi:10.1038/nm1541. PMID 17334373. 
  5. ^ Mundell, E.J. (March 5, 2007). "Scientists Discover 'Natural Barrier' to HIV", HealthDay News via sexualhealth.e-healthsource.com. Retrieved on 2008-07-13. 

External links

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