Characterization of dendritic cells from human oral mucosa: a new Langerhans' cell type with high constitutive FcepsilonRI expression.
BACKGROUND
The oral mucosa represents a unique immunologic unit with a high frequency of native allergen contact within the gastrointestinal tract in which immune tolerance is the natural outcome of allergen contact. Although Langerhans' cells (LC), known to play a crucial role in initiating allergen-dependent immune responses in the skin, have also been detected in the oral mucosa, little is known about their phenotype and exact physiologic role.


OBJECTIVE
To elucidate whether LC from oral mucosa (oLC) differ from skin LC (sLC), these cells were subjected to detailed comparative analysis.


METHODS
Crude epidermal and oral mucosa cell suspensions were prepared by trypsinization. oLC and sLC were compared phenotypically by flow cytometry techniques and functionally in T-cell proliferation assays.


RESULTS
In contrast to sLC, freshly isolated oLC expressed significantly higher amounts of MHC class I and II, as well as costimulatory molecules CD40, CD80/B7.1, and CD86/B7.2. oLC displayed FcgammaRIII/CD16 and FcgammaRI/CD64. Most surprisingly, oLC constitutively expressed the high affinity receptor for IgE (FcepsilonRI) even in nonatopic donors. FcepsilonRI expression on oLC was further increased and correlated with the serum IgE levels in atopic individuals. oLC showed a higher allogeneic stimulatory activity than sLC, whereas the activation of autologous T cells correlated to the FcepsilonRI expression.


CONCLUSIONS
Taken together, our results strongly indicate that oLC profoundly differ from their skin counterparts. The constitutive high expression of FcepsilonRI on oLC could point to particular skills of these cells within the regional immune system of the oral mucosa.
Allam
Jean-Pierre
JP
Department of Dermatology, Friedrich-Wilhelms-University, Bonn, Germany.
Novak
Natalija
N
Fuchs
Christian
C
Asen
Sylvia
S
Bergé
Stefaan
S
Appel
Thorsten
T
Geiger
Elisabeth
E
Kochan
Jarema P
JP
Bieber
Thomas
T
D015703:Antigens, CD / Q000032:analysis; D018122:B7-1 Antigen / Q000032:analysis; D051940:B7-2 Antigen; D019013:CD40 Antigens / Q000032:analysis; D003713:Dendritic Cells / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000032:analysis; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D007801:Langerhans Cells / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000032:analysis; D009061:Mouth Mucosa / Q000276:immunology*; D017455:Receptors, IgE / Q000032:analysis*; D013601:T-Lymphocytes / Q000276:immunology
D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D019013:CD40 Antigens; C497964:CD86 protein, human; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D008562:Membrane Glycoproteins; D017455:Receptors, IgE