Peripheral blood dendritic cells express Fc epsilon RI as a complex composed of Fc epsilon RI alpha- and Fc epsilon RI gamma-chains and can use this receptor for IgE-mediated allergen presentation.
Originally limited to basophils and mast cells, the spectrum of high affinity IgE receptor (Fc epsilon RI-bearing cells has expanded recently to include Langerhans cells, dermal dendritic cells (DC), monocytes, and eosinophils. As a result of studies on the distribution, structure, and function of Fc epsilon RI on APCs, we discovered a minor nonbasophil, nonmonocyte PBMC population that can bind IgE via Fc epsilon RI. This receptor occurs on the surface of these cells as a multimeric structure containing Fc epsilon RI alpha- and Fc epsilon RI gamma-chains but, unlike its counterpart on basophils, lacking Fc epsilon RI beta. Further experiments revealed that these Fc epsilon RI alpha gamma-expressing cells closely resemble peripheral blood DC by immunophenotype (HLA-DRhigh, HLA-DQhhigh; CD4+, CD11a+, CD32+, CD33+, B7/2 (CD86)+; CD11blow, CD14low, CD40low, CD54low, CD64low) and cell morphology. These features allowed us to isolate Fc epsilon RI-expressing DC from the peripheral blood and to investigate their immunostimulatory properties. We found Fc epsilon RI-positive DC to be efficient stimulators of both primary (allogeneic MLR) and Fc epsilon RI/IgE-dependent, secondary T cell responses at low cell numbers. Thus, Fc epsilon RI-expressing DC may not only amplify established type I allergic immune reactions but, unlike Fc epsilon RI-positive semiprofessional APCs, may be able to prime naive T cells to common and/or cryptic epitopes of IgE-reactive Ags.
Maurer
D
D
Department of Dermatology, University of Vienna Medical School, Austria.
Fiebiger
S
S
Ebner
C
C
Reininger
B
B
Fischer
G F
GF
Wichlas
S
S
Jouvin
M H
MH
Schmitt-Egenolf
M
M
Kraft
D
D
Kinet
J P
JP
Stingl
G
G
D000485:Allergens / Q000276:immunology*; D017951:Antigen Presentation; D001483:Base Sequence; D002460:Cell Line; D003713:Dendritic Cells / Q000145:classification / Q000276:immunology / Q000378:metabolism*; D006684:HLA-DR Antigens; D006801:Humans; D007073:Immunoglobulin E / Q000502:physiology*; D016130:Immunophenotyping; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D018950:Lipopolysaccharide Receptors; D008969:Molecular Sequence Data; D017455:Receptors, IgE / Q000096:biosynthesis* / Q000737:chemistry* / Q000502:physiology
D000485:Allergens; D006684:HLA-DR Antigens; D018950:Lipopolysaccharide Receptors; D017455:Receptors, IgE; D007073:Immunoglobulin E