Immature DC (iDC) / Langerhans Cells

Immature dendritic cells (iDCs), also known as Langerhans cells (LCs), are a specialized subset of antigen-presenting cells (APCs) that play a crucial role in the immune surveillance of the epidermis, the outermost layer of the skin. These cells are strategically positioned to act as immune sentinels, capturing antigens at the skin barrier and migrating to lymph nodes to prime T- and B-lymphocytes, leading to a variety of immune responses
Neagu et al. 2022 J Pers Med. 12(12): 2072

Langerhans cells have been shown to be capable of inducing the proliferation of skin-resident CD8 memory T cells, which are important for the body's defense against previously encountered pathogens
Igyártó & Kaplan 2013
Neagu et al. 2022 J Pers Med. 12(12): 2072

They are also more efficient at priming CD8+ T cells compared to interstitial dendritic cells, highlighting their significance in initiating immune responses
Bachy et al. 2013 Proc Natl Acad Sci USA 110(8): 3041-6
Neagu et al. 2022 J Pers Med. 12(12): 2072

The differentiation of iDCs/LCs is influenced by local estrogen levels and estrogen-mediated signaling events in the skin, suggesting a hormonal regulation of their maturation and function
Mao et al., 2005
Neagu et al. 2022 J Pers Med. 12(12): 2072

Upon exposure to pro-inflammatory cytokines, iDCs/LCs can be induced to mature, a process that is critical for their ability to stimulate immune responses
Zhou et al. 2002
Neagu et al. 2022 J Pers Med. 12(12): 2072

Cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-1 (IL-1) are involved in the maturation of murine epidermal iDCs/LCs into potent immunostimulatory dendritic cells
Heufler et al., 1987
Neagu et al. 2022 J Pers Med. 12(12): 2072

They are the best characterized nonlymphoid dendritic cells and are known to migrate into the dermis upon maturation
Neagu et al. 2022 J Pers Med. 12(12): 2072

Additionally, they express receptors for immune complexes and the third component of complement (Fc and C3 receptors), which play a role in immune responses
Stingl et al. 1977
Tamaki et al. 1979
Neagu et al. 2022 J Pers Med. 12(12): 2072

Dendritic Cells (DCs) reside in periphery as immature cells with a high ability to endocytose target antigens.
Steinman et al. 1999 Hum Immunol 60(7): 562-567

Epidermal Immature DC (iDC) / Langerhans Cells are the best characterized nonlymphoid Dendritic Cells (DCs)
Steinman 1991

Immature DC (iDC) / Langerhans Cells move into the dermis
Steinman 1991

Immature DC (iDC) / Langerhans Cells are the major APCs (antigen presenting cells) in epidermis .
Katz et al., 1979 Nature 282: 324-326

In summary, iDCs/LCs are pivotal in the immune defense of the skin, with their ability to capture antigens, migrate to lymph nodes, and prime T cells. Their maturation and function are regulated by cytokines and hormonal signals, and they exhibit a unique capacity to induce memory T cell responses, which is crucial for long-term immunity.