Follicular dendritic cell (FDC)-FcgammaRIIB engagement via immune complexes induces the activated FDC phenotype associated with secondary follicle development
| Autor: | Rania M. El Sayed, Mohey Eldin M. El Shikh, John G. Tew, Andras K. Szakal |
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| Rok vydání: | 2006 |
| Předmět: |
Immunology
Vascular Cell Adhesion Molecule-1 Antigen-Antibody Complex Biology Flow cytometry chemistry.chemical_compound Mice Immune system medicine Immunology and Allergy Animals RNA Messenger VCAM-1 ICAM-1 Messenger RNA B-Lymphocytes Follicular dendritic cells medicine.diagnostic_test Reverse Transcriptase Polymerase Chain Reaction Macrophages Receptors IgG Flow Cytometry Intercellular Adhesion Molecule-1 Molecular biology Immunohistochemistry In vitro Immune complex Mice Mutant Strains Phenotype chemistry Lymph Nodes Dendritic Cells Follicular |
| Zdroj: | European journal of immunology. 36(10) |
| ISSN: | 0014-2980 |
| Popis: | Follicular dendritic cell (FDC)-FcgammaRIIB levels are up-regulated 1-3 days after challenge of actively immunized mice with Ag. This kinetics suggested that memory cells are not driving this response, prompting the hypothesis that immune complex (IC)-FDC interactions lead to FDC activation. To test this, mice passively immunized with anti-OVA Ab were OVA challenged to produce IC. After 3 days, levels of IC, FcgammaRIIB, ICAM-1, and VCAM-1 on FDC were analyzed. FDC were also stimulated with IC in vitro, and mRNA for FcgammaRIIB, ICAM-1, and VCAM-1 was quantified by quantitative RT-PCR. IC labeling in passively immunized WT and FcgammaRIIB-/- mice revealed five to six FDC-reticula per LN midsagittal section. In WT mice, these IC-bearing FDC-reticula corresponded with FDC-reticula labeling for FcgammaRIIB, ICAM-1, and VCAM-1. Increases in these molecules on IC-stimulated FDC were confirmed by flow cytometry. In marked contrast, in FcgammaRIIB-/- mice, no increased VCAM-1 or ICAM-1 was seen on IC-bearing FDC-reticula or on purified FDC. Addition of IC in vitro resulted in dramatic increases in mRNA for FcgammaRIIB, ICAM-1 and VCAM-1 in WT FDC, but not in FDC from FcgammaRIIB-/- mice, 2.4G2-pretreated WT FDC, B cells, or macrophages. Thus, although FDC-FcgammaRIIB was not essential for IC trapping, engagement of FDC-FcgammaRIIB with IC initiated an FDC activation pathway. |
| Databáze: | OpenAIRE |
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