title: Ex VivoExpanded Autologous Polyclonal Regulatory T Cells Suppress Inhibitor Formation in Hemophilia.
abstract: Adoptive cell therapy utilizingex vivoexpanded polyclonal CD4+CD25+FOXP3+regulatory T cells (Treg) is in use in clinical trials for the treatment of type 1 diabetes and prevention of graft vs host disease in bone marrow transplantation. Here we seek to evaluate this approach in the treatment of inherited protein deficiencies,i.e.hemophilia, which is often complicated by antibody formation against the therapeutic protein. Treg from mice that express GFP-marked FoxP3 were highly purified by two-step magnetic/flow sorting andex vivoexpanded 50- to 80-fold over a 2-week culture period upon stimulation with antibody-coated microbeads. FoxP3 expression was maintained in >80% of expanded Treg, which also expressed high levels of CD62L and CTLA-4. Transplanted Treg suppressed inhibitory antibody formation against coagulation factors VIII and IX in protein and gene therapies in strain-matched hemophilia A and B mice, including in mice with pre-existing antibodies. Although transplanted Treg became undetectable within two weeks, suppression persisted for >2 months. Additional studies suggested that antigen-specific suppression emerged due to induction of endogenous Treg. The outcomes of these studies support the concept that cell therapy withex vivoexpanded autologous Treg can be used successfully to minimize immune responses in gene and protein replacement therapies.
authors.affiliation: Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Debalina
authors.initials: D
authors.lastname: Sarkar
authors.affiliation: Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Moanaro
authors.initials: M
authors.lastname: Biswas
authors.affiliation: Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA 02115. USA.
authors.forename: Gongxian
authors.initials: G
authors.lastname: Liao
authors.affiliation: Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Howard R
authors.initials: HR
authors.lastname: Seay
authors.affiliation: Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA.
authors.forename: George Q
authors.initials: GQ
authors.lastname: Perrin
authors.affiliation: Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Markusic
authors.affiliation: Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Brad E
authors.initials: BE
authors.lastname: Hoffman
authors.affiliation: Department of Pathology, Immunology and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Todd M
authors.initials: TM
authors.lastname: Brusko
authors.affiliation: Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA 02115. USA.
authors.forename: Cox
authors.initials: C
authors.lastname: Terhorst
authors.affiliation: Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Roland W
authors.initials: RW
authors.lastname: Herzog
keywords: AAV vector; Regulatory T cells; cell therapy; hemophilia; tolerance