title: Immunomagnetic isolation of CD4+CD25+FoxP3+ natural T regulatory lymphocytes for clinical applications.
abstract: Although CD4(+)/CD25(+) T regulatory cells (T(regs)) are a potentially powerful tool in bone marrow transplantation, a prerequisite for clinical use is a cell-separation strategy complying with good manufacturing practice guidelines. We isolated T(regs) from standard leukapheresis products using double-negative selection (anti-CD8 and anti-CD19 monoclonal antibodies) followed by positive selection (anti-CD25 monoclonal antibody). The final cell fraction (CD4(+)/CD25(+)) showed a mean purity of 93.6% +/- 1.1. Recovery efficiency was 81.52% +/- 7.4. The CD4(+)/CD25(+bright) cells were 28.4% +/- 6.8. The CD4(+)/CD25(+) fraction contained a mean of 51.9% +/- 15.1 FoxP3 cells and a mean of 18.9% +/- 11.5 CD127 cells. Increased FoxP3 and depleted CD127 mRNAs in CD4(+)CD25(+)FoxP3(+) cells were in line with flow cytometric results. In Vbeta spectratyping the complexity scores of CD4(+)/CD25(+) cells and CD4(+)/CD25(-) cells were not significantly different, indicating that T(regs) had a broad T cell receptor repertoire. The inhibition assay showed that CD4(+)/CD25(+) cells inhibited CD4(+)/CD25(-) cells in a dose-dependent manner (mean inhibition percentages: 72.4 +/- 8.9 [ratio of T responder (T(resp)) to T(regs), 1:2]; 60.8% +/- 20.5 (ratio of T(resp) to T(regs), 1:1); 25.6 +/- 19.6 (ratio of T(resp) to T(regs), 1:0.1)). Our study shows that negative/positive T(reg) selection, performed using the CliniMACS device and reagents, enriches significantly CD4(+)CD25(+)FoxP3(+) cells endowed with immunosuppressive capacities. The CD4(+)CD25(+)FoxP3(+) population is a source of natural T(reg) cells that are depleted of CD8(+) and CD4(+)/CD25(-) reacting clones which are potentially responsible for triggering graft-versus-host disease (GvHD). Cells isolated by means of this approach might be used in allogeneic haematopoietic cell transplantation to facilitate engraftment and reduce the incidence and severity of GvHD without abrogating the potential graft-versus-tumour effect.
authors.affiliation: Department of Internal Medicine and Public Health, Chair of Hematology, University of L'Aquila, Italy. mauro.diianni@cc.univaq.it
authors.forename: M
authors.initials: M
authors.lastname: Di Ianni
authors.forename: B
authors.initials: B
authors.lastname: Del Papa
authors.forename: D
authors.initials: D
authors.lastname: Cecchini
authors.forename: E
authors.initials: E
authors.lastname: Bonifacio
authors.forename: L
authors.initials: L
authors.lastname: Moretti
authors.forename: T
authors.initials: T
authors.lastname: Zei
authors.forename: R Iacucci
authors.initials: RI
authors.lastname: Ostini
authors.forename: F
authors.initials: F
authors.lastname: Falzetti
authors.forename: L
authors.initials: L
authors.lastname: Fontana
authors.forename: G
authors.initials: G
authors.lastname: Tagliapietra
authors.forename: C
authors.initials: C
authors.lastname: Maldini
authors.forename: M F
authors.initials: MF
authors.lastname: Martelli
authors.forename: A
authors.initials: A
authors.lastname: Tabilio
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000276:immunology*; D006801:Humans; D018189:Immunomagnetic Separation; D016130:Immunophenotyping / Q000379:methods; D053645:Interleukin-2 Receptor alpha Subunit / Q000032:analysis / Q000276:immunology*; D053666:Interleukin-5 Receptor alpha Subunit / Q000032:analysis; D053699:Interleukin-7 Receptor alpha Subunit / Q000235:genetics; D007937:Leukapheresis / Q000379:methods; D008875:Middle Aged; D010641:Phenotype; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D032681:Spectral Karyotyping / Q000379:methods
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D053645:Interleukin-2 Receptor alpha Subunit; D053666:Interleukin-5 Receptor alpha Subunit; D053699:Interleukin-7 Receptor alpha Subunit