Langerhans cells (LC), the epidermal contingent of the dendritic cell (DC) lineage, migrate from skin to regional lymph nodes to initiate primary immune responses against Ag encountered in skin. Because E-cadherin mediates LC-keratinocyte adhesion, E-cadherin expression and/or function must be modulated during LC migration. To facilitate studies of LC/DC cadherin biology, we defined culture conditions that allowed expansion of LC-like cells from fetal murine skin. Fetal skin-derived dendritic cells (FSDDC) were propagated from C57BL/6 day 16 fetal skin in GM-CSF- and CSF-1-supplemented media. After 14 days, aggregates of E-cadherin+ FSDDC (FSDDC-A) that resembled freshly-obtained LC with regard to phenotype and function were isolated. Nonadherent FSDDC (FSDDC-NA) with dendritic morphology, surface phenotype identical to that of interdigitating DC and potent allostimulatory capacity were released from FSDDC-A with continued incubation. A survey of cytokine mRNAs expressed by FSDDC revealed that FSDDC-A expressed predominantly TNF-α, TGF-β1, and MIF mRNA. In contrast, FSDDC-NA exhibited de novo expression of IL-1β, IL-12 (p40), increased levels of TNF-α and decreased MIF mRNA. Neutralizing anti-E-cadherin mAb dissociated FSDDC-A into single cells, whereas functionally inactive anti-E-cadherin mAb and mAb reactive with other adhesion molecules did not, demonstrating that adhesion within FSDDC-A was E-cadherin-mediated. FSDDC-A also preferentially adhered to E-cadherin-transfected fibroblasts. Spontaneous dissociation of FSDDC-A was accompanied by a reduction in cell surface E-cadherin expression. The availability of large numbers of cells with characteristics of LC in situ that spontaneously mature into interdigitating DC will permit detailed studies of LC/DC cadherin biology and LC/DC differentiation.
|Number of pages||9|
|Journal||Journal of Immunology|
|State||Published - Dec 1 1997|