Langerhans Cells- Dendritic-shaped cells derived from bone marrow; found in epidermis, lymph nodes, and spleen; excellent antigenpresenting cells but poorly phagocytic
- After antigen captured, LC migrates to regional lymph node and presents Ag to T cells (as processed peptide with MHC molecule) → subsequent T cell activation
- Adhere to keratinocytes via E-cadherin; express B7 (CD80 or 86) after activation by antigen
- Identifed by cytoplasmic rod-shaped or racket-shaped organelles (Birbeck granules) on EM
- LC markers: CD1a (exclusive to LC), S100, vimentin, and langerin (now useful marker)
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