1998 Fiscal Year Final Research Report Summary
Development of antigen-specific B cell elimination by recombinant toxins in autoimmune diseases
| Project/Area Number |
09557064
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Dermatology
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| Research Institution | Keio University |
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Principal Investigator |
AMAGAI Masayuki Keio University, School of Medicine, Assistant Professor, 医学部, 専任講師 (90212563)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAYANAGI Atsushi Keio University, School of Medicine, Instructor, 医学部, 助手 (80245464)
SHIMIZU Nobuyoshi Keio University, School of Medicine, Professor, 医学部, 教授 (50162706)
SHIMIZU Hiroshi Keio University, School of Medicine, Associate Professor, 医学部, 助教授 (00146672)
NISHIKAWA Takeji Keio University, School of Medicine, Professor, 医学部, 教授 (50051579)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Autoimmune disease / Pemphigus / B cell / Disease-specific therapy / Recombinant toxin / Cadherin / Desmoglein / Cell adhesion |
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| Research Abstract |
Pemphigus vulgaris (PV) is an autoimmune blistering disease characterized by circulating pathogenic IgG antibodies against desmoglein 3 (Dsg3). The purpose of this study was to develop chimeric molecules for specific recognition and elimination of autoimmune B cells in PV.Mouse hybridoma cell lines producing anti-Dsg3 antibody (5H10, 12A2) were developed as an in vitro model system for B cell targeting. Dsg3-GFg a baculoprotein containing the entire extracellular domain of Dsg3 fused with green fluorescence protein, recognized and targeted the hybridoma cells through their surface immunoglobulin receptors in an antigen-specific way. The epitopes of these monoclonal antibodies were mapped on the amino-terminal EC1 and part of EC2, a region considered functionally important in cadherins. Chimeric toxin molecules containing the mapped region (Dsg3_N1) and modified Pseudomonas exotoxin (PE) were produced in bacteria (Dsg3_N1-PF4O-KDEL, PE37-Dsg3_N1-KDEL) and tested in vitro on hybridoma cell lines. The chimeric toxins, but not Dsg3_N1 alone, showed dose-dependent toxic activity with a reduction in hybridoma cell number to 40-60% of toxin-negative control cultures, compared with little or no effect on anti-Dsg3-negative hybridoma cells. Furthermore, these toxins showed toxic effects on anti-Dsg3 IgG-producing B cells from Dsg3_N1-immunized mice, with a 60% reduction in cell number compared with Dsg3_N1 alone. Thus specific recognition and targeting of antigen-specific B cells in PV was demonstrated and this strategy may hold promise as a future therapeutic option for PV and other autoimmune diseases.
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