title: Long-lived plasma cells are early and constantly generated in New Zealand Black/New Zealand White F1 mice and their therapeutic depletion requires a combined targeting of autoreactive plasma cells and their precursors.
abstract: BACKGROUND
  Autoantibodies contribute significantly to the pathogenesis of systemic lupus erythematosus (SLE). Unfortunately, the long-lived plasma cells (LLPCs) secreting such autoantibodies are refractory to conventional immunosuppressive treatments. Although generated long before the disease becomes clinically apparent, it remains rather unclear whether LLPC generation continues in the established disease. Here, we analyzed the generation of LLPCs, including autoreactive LLPCs, in SLE-prone New Zealand Black/New Zealand White F1 (NZB/W F1) mice over their lifetime, and their regeneration after depletion.
  
  
  METHODS
  Bromodeoxyuridine pulse-chase experiments in mice of different ages were performed in order to analyze the generation of LLPCs during the development of SLE. LLPCs were enumerated by flow cytometry and autoreactive anti-double-stranded DNA (anti-dsDNA) plasma cells by enzyme-linked immunospot (ELISPOT). For analyzing the regeneration of LLPCs after depletion, mice were treated with bortezomib alone or in combination with cyclophosphamide and plasma cells were enumerated 12 hours, 3, 7, 11 and 15 days after the end of the bortezomib cycle.
  
  
  RESULTS
  Autoreactive LLPCs are established in the spleen and bone marrow of SLE-prone mice very early in ontogeny, before week 4 and before the onset of symptoms. The generation of LLPCs then continues throughout life. LLPC counts in the spleen plateau by week 10, but continue to increase in the bone marrow and inflamed kidney. When LLPCs are depleted by the proteasome inhibitor bortezomib, their numbers regenerate within two weeks. Persistent depletion of LLPCs was achieved only by combining a cycle of bortezomib with maintenance therapy, for example cyclophosphamide, depleting the precursors of LLPCs or preventing their differentiation into LLPCs.
  
  
  CONCLUSIONS
  In SLE-prone NZB/W F1 mice, autoreactive LLPCs are generated throughout life. Their sustained therapeutic elimination requires both the depletion of LLPCs and the inhibition of their regeneration.
authors.affiliation: Department of Rheumatology and Clinical Immunology, Charité University Hospital Berlin, Charitéplatz 1, 10117, Berlin, Germany. Taddeo@drfz.de.|German Rheumatism Research Centre, a Leibniz Institute, Charitéplatz 1, 10117, Berlin, Germany. Taddeo@drfz.de.
authors.forename: Adriano
authors.initials: A
authors.lastname: Taddeo
authors.affiliation: Department of Rheumatology and Clinical Immunology, Charité University Hospital Berlin, Charitéplatz 1, 10117, Berlin, Germany. Khodadadi@drfz.de.|German Rheumatism Research Centre, a Leibniz Institute, Charitéplatz 1, 10117, Berlin, Germany. Khodadadi@drfz.de.
authors.forename: Laleh
authors.initials: L
authors.lastname: Khodadadi
authors.affiliation: Department of Rheumatology and Clinical Immunology, Charité University Hospital Berlin, Charitéplatz 1, 10117, Berlin, Germany. voigt@drfz.de.
authors.forename: Caroline
authors.initials: C
authors.lastname: Voigt
authors.affiliation: Department of Rheumatology and Clinical Immunology, Charité University Hospital Berlin, Charitéplatz 1, 10117, Berlin, Germany. bimba.hoyer@charite.de.|German Rheumatism Research Centre, a Leibniz Institute, Charitéplatz 1, 10117, Berlin, Germany. bimba.hoyer@charite.de.
authors.forename: Imtiaz M
authors.initials: IM
authors.lastname: Mumtaz
authors.affiliation: Department of Rheumatology and Clinical Immunology, Charité University Hospital Berlin, Charitéplatz 1, 10117, Berlin, Germany. cheng@drfz.de.
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Cheng
authors.affiliation: German Rheumatism Research Centre, a Leibniz Institute, Charitéplatz 1, 10117, Berlin, Germany. moser@drfz.de.
authors.forename: Katrin
authors.initials: K
authors.lastname: Moser
authors.affiliation: Department of Rheumatology and Clinical Immunology, Charité University Hospital Berlin, Charitéplatz 1, 10117, Berlin, Germany. tobias.alexander@charite.de.|German Rheumatism Research Centre, a Leibniz Institute, Charitéplatz 1, 10117, Berlin, Germany. tobias.alexander@charite.de.
authors.forename: Tobias
authors.initials: T
authors.lastname: Alexander
authors.affiliation: Institute for Systemic Inflammation Research, University of Luebeck, Ratzeburger Allee 160, 23562, Luebeck, Germany. Rudolf.Manz@uksh.de.
authors.forename: Rudolf A
authors.initials: RA
authors.lastname: Manz
authors.affiliation: German Rheumatism Research Centre, a Leibniz Institute, Charitéplatz 1, 10117, Berlin, Germany. radbruch@drfz.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Radbruch
authors.affiliation: Department of Rheumatology and Clinical Immunology, Charité University Hospital Berlin, Charitéplatz 1, 10117, Berlin, Germany. falk.hiepe@charite.de.|German Rheumatism Research Centre, a Leibniz Institute, Charitéplatz 1, 10117, Berlin, Germany. falk.hiepe@charite.de.
authors.forename: Falk
authors.initials: F
authors.lastname: Hiepe
authors.affiliation: Department of Rheumatology and Clinical Immunology, Charité University Hospital Berlin, Charitéplatz 1, 10117, Berlin, Germany. bimba.hoyer@charite.de.|German Rheumatism Research Centre, a Leibniz Institute, Charitéplatz 1, 10117, Berlin, Germany. bimba.hoyer@charite.de.
authors.forename: Bimba F
authors.initials: BF
authors.lastname: Hoyer
mesh_terms: D000818:Animals; D001323:Autoantibodies / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D016922:Cellular Senescence / Q000502:physiology; D018450:Disease Progression; D005260:Female; D008180:Lupus Erythematosus, Systemic / Q000378:metabolism* / Q000473:pathology* / Q000628:therapy; D051379:Mice; D008814:Mice, Inbred NZB; D010950:Plasma Cells / Q000378:metabolism* / Q000473:pathology*
chemical_list: D001323:Autoantibodies