title: Induction of T-cell development by Delta-like 4-expressing fibroblasts.
abstract: The thymus provides a unique environment for the induction of T-cell lineage commitment and differentiation, which is predicted by specific Notch ligand-receptor interactions on epithelial cells and lymphoid progenitors, respectively. Accordingly, a bone marrow-derived stromal cell line (OP9) ectopically expressing the Notch ligand Delta-like 1 (Dll1) or Dll4 (OP9-DL1 and OP9-DL4, respectively) gains the ability to recapitulate thymus-like function, supporting T-cell differentiation of both mouse and human progenitors. In this study, we extend these findings by demonstrating that, unlike the NIH3T3 cell line, mouse primary fibroblasts made to express Dll4 (mFibro-DL4) acquire the capacity to promote and support T-cell development from hematopoietic stem cells (HSCs) into TCRαβ(+), CD4(+) and CD8(+) T-lineage cells. However, mFibro-DL4 cells showed a lower efficiency of T-cell generation than OP9-DL4 cells did. Nevertheless, progenitor T-cells (CD117(+) CD44(+) CD25(+)) generated in HSC/mFibro-DL4 co-cultures, when intravenously transferred into immunodeficient (Rag2(-/-) γc(-/-)) mice, home to the thymus, undergo differentiation, and give rise to mature T-cells that go on to populate the periphery. Surprisingly, primary human fibroblast cells expressing Dll4 showed very low efficiency in supporting human T-lineage differentiation, which could not be improved by blocking myelopoiesis. Nevertheless, mFibro-DL4 cells could support human T-cell lineage differentiation. Our results provide a functional framework for the induction of T-cell development using easily accessible fibroblasts made to express Dll4. These cells, which are amenable for in vitro applications, can be further utilized in the design of individualized systems for T-cell production, with implications for the treatment of immunodeficiencies.
authors.affiliation: Department of Immunology, Sunnybrook Research Institute, University of Toronto, Toronto, Ontario, M4N 3M5 Canada.
authors.forename: Mahmood
authors.initials: M
authors.lastname: Mohtashami
authors.forename: Divya K
authors.initials: DK
authors.lastname: Shah
authors.forename: Korosh
authors.initials: K
authors.lastname: Kianizad
authors.forename: Geneve
authors.initials: G
authors.lastname: Awong
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Zúñiga-Pflücker
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002135:Calcium-Binding Proteins; D002454:Cell Differentiation; D002460:Cell Line; D060966:Clonal Selection, Antigen-Mediated; D018920:Coculture Techniques; D004268:DNA-Binding Proteins / Q000235:genetics; D005347:Fibroblasts / Q000276:immunology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000378:metabolism; D013950:Thymus Gland / Q000276:immunology*; D019076:Transgenes / Q000235:genetics
chemical_list: D002135:Calcium-Binding Proteins; C512941:DLK1 protein, human; D004268:DNA-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C499308:Rag2 protein, mouse; D016693:Receptors, Antigen, T-Cell, alpha-beta
keywords: Delta-like 4; Notch; T-cells; stromal cells; thymus