title: Interleukin-7-engineered mesenchymal cells: in vitro effects on naive T-cell population.
abstract: T-cell homeostasis is regulated by several molecules; among these, interleukin (IL)-7 plays an essential role in the survival and homeostatic proliferation of peripheral naive T cells. In a previous study, we investigated whether human mesenchymal stromal cells (MSCs) could be engineered with the IL-7 gene to produce functional level of this cytokine. In the present study, we analyzed the impact of different quantities of IL-7 produced by MSCs on the survival and proliferation of a negative immunoselected naive (CD3(+)/CD45RA(+)) T-cell population. Co-cultivation of peripheral naive T cells with MSCs producing low (16 pg/mL) or high (1000 pg/mL) IL-7 levels or in the presence of exogenous IL-7 (0.01 ng/mL and 100 ng/mL) maintained the CD3(+)/CD45RA(+) naive T-cell phenotype. Chemokine receptor CCR7(+) expression was also maintained among this T-cell population. Naive T-cell molecular characteristics were maintained as assessed by the Vbeta spectratyping complexity score, which showed the maintenance of a broad T-cell repertoire. No Th1 or Th2 differentiation was observed, as assessed by interferon-gamma or IL-4 accumulation. In contrast, only MSCs producing high amounts of IL-7 caused increased activation (CD25 31.2% +/- 12% vs 10% +/- 3.5%; P < .05), proliferation (CD71 17.8+/-7% vs 9.3%+/-3, P < .05), apoptosis (assessed by annexin V: 18.6% +/- 5% vs 14.9% +/- 2.6%; P > .05), and the phase S cell cycle (15% vs 6.9%, P > .05). Exogenous IL-7 exhibited no significant effect. In conclusion, we demonstrated that IL-7 produced by MSCs has a dose-independent effect on naive T-cell survival while exerting a dose-dependent effect on activation/proliferation. Due to the continuous production of IL-7 by engineered cells, our system is more efficacious than exogenous IL-7.
authors.affiliation: Hematology and Clinical Immunology Section, Department of Clinical and Experimental Medicine, Perugia University, Perugia, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Sportoletti
authors.forename: Beatrice
authors.initials: B
authors.lastname: Del Papa
authors.forename: Mariangela
authors.initials: M
authors.lastname: De Ioanni
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Moretti
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Bonifacio
authors.forename: Vania
authors.initials: V
authors.lastname: Lanterna
authors.forename: Alain
authors.initials: A
authors.lastname: Bell
authors.forename: Katia
authors.initials: K
authors.lastname: Fettucciari
authors.forename: Eugenia
authors.initials: E
authors.lastname: Carnevali
authors.forename: Tiziana
authors.initials: T
authors.lastname: Zei
authors.forename: Franca
authors.initials: F
authors.lastname: Falzetti
authors.forename: Massimo F
authors.initials: MF
authors.lastname: Martelli
authors.forename: Antonio
authors.initials: A
authors.lastname: Tabilio
authors.forename: Mauro
authors.initials: M
authors.lastname: Di Ianni
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D017209:Apoptosis; D002478:Cells, Cultured / Q000166:cytology / Q000378:metabolism; D018920:Coculture Techniques; D004305:Dose-Response Relationship, Drug; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D005818:Genetic Engineering; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D016130:Immunophenotyping; D015851:Interleukin-7 / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000187:drug effects* / Q000378:metabolism; D054400:Receptors, CCR7; D019707:Receptors, Chemokine / Q000032:analysis; D011993:Recombinant Fusion Proteins / Q000502:physiology; D012190:Retroviridae / Q000235:genetics; D016196:S Phase; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology; D014161:Transduction, Genetic
chemical_list: D015703:Antigens, CD; C515370:CCR7 protein, human; D015851:Interleukin-7; D054400:Receptors, CCR7; D019707:Receptors, Chemokine; D011993:Recombinant Fusion Proteins