Identification of antigen-capturing cells as basophils.
Binding of intact Ag is a hallmark of Ag-specific B cells. Apart from B cells, a small number of non-B cells can bind Ag with comparable efficacy as B cells and are found in the peripheral blood, spleen, and bone marrow of mice. This population has been observed for a long time and recently named "Ag-capturing cells." Their identity remained enigmatic. In this study, we show that these cells are basophilic granulocytes. Their ability to capture Ags is dependent on surface IgE receptors and on Ag-specific plasma IgE molecules appearing after immunization. Several surface markers including surface bound IgE, IL-3R, CD45, CD16/32, and the chemokine receptor CCR2 were used to clearly identify these cells. Cross-linkage of surface Igs results in the release of large amounts of IL-4 and IL-6. The data identify basophils as Ag-capturing cells and support the concept of basophils as important regulators of humoral immune responses.
Mack
Matthias
M
Klinikum, University of Regensburg, Regensburg, Germany. matthias.mack@klinik.uni-regensburg.de
Schneider
Martin A
MA
Moll
Cordula
C
Cihak
Josef
J
Brühl
Hilke
H
Ellwart
Joachim W
JW
Hogarth
Mark P
MP
Stangassinger
Manfred
M
Schlöndorff
Detlef
D
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology / Q000378:metabolism; D000941:Antigens / Q000276:immunology / Q000378:metabolism*; D016175:B-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D001491:Basophils / Q000276:immunology* / Q000378:metabolism*; D001665:Binding Sites / Q000276:immunology; D002448:Cell Adhesion / Q000276:immunology; D002478:Cells, Cultured; D000939:Epitopes / Q000502:physiology; D008164:Luminescent Proteins / Q000008:administration & dosage / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D010798:Phycocyanin / Q000008:administration & dosage / Q000276:immunology / Q000378:metabolism; D017455:Receptors, IgE / Q000502:physiology
D000941:Antigens; D000939:Epitopes; D008164:Luminescent Proteins; D017455:Receptors, IgE; C002497:allophycocyanin; D010798:Phycocyanin