In situ transduction of stromal cells and thymocytes upon intrathymic injection of lentiviral vectors.
BACKGROUND
The thymus is the primary site for T-cell development and induction of self-tolerance. Previous approaches towards manipulation of T-cell differentiation have used intrathymic injection of antigens, as proteins, cells or adenoviruses, leading to transient expression of the foreign protein. Lentiviral vectors, due to their unique ability to integrate into the genome of quiescent cells, may be best suited for long-term expression of a transgene in the thymus.


RESULTS
Young adult mice were injected in the thymus with lentiviral vectors expressing eGFP or the hemaglutinin of the Influenza virus under the control of the ubiquitous phospho glycerate kinase promoter. Thymi were examined 5 to 90 days thereafter directly under a UV-light microscope and by flow cytometry. Intrathymic injection of lentiviral vectors predominantly results in infection of stromal cells that could be detected for at least 3 months. Importantly, hemaglutinin expression by thymic stromal cells mediated negative selection of thymocytes expressing the cognate T-cell receptor. In addition and despite the low multiplicity of infection, transduced thymocytes were also detected, even 30 days after injection.


CONCLUSIONS
Our results demonstrate that intrathymic delivery of a lentiviral vector is an efficient means for stable expression of a foreign gene in the thymus. This new method of gene delivery may prove useful for induction of tolerance to a specific antigen and for gene therapy of severe combined immunodeficiencies.
Marodon
Gilles
G
UPMC/CNRS UMR7087, 83 Bd de l'Hôpital, Bât CERVI, 75651 Paris, France. gilles.marodon@chups.jussieu.fr
Klatzmann
David
D
D000818:Animals; D017637:Clonal Deletion; D017930:Genes, Reporter; D005813:Genes, Synthetic; D005822:Genetic Vectors / Q000008:administration & dosage* / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology; D007108:Immune Tolerance; D007267:Injections; D016086:Lentivirus / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010735:Phosphoglycerate Kinase / Q000235:genetics; D011401:Promoter Regions, Genetic; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D017154:Stromal Cells / Q000166:cytology / Q000821:virology; D037182:T-Cell Antigen Receptor Specificity; D013601:T-Lymphocytes / Q000166:cytology / Q000821:virology; D013950:Thymus Gland / Q000166:cytology* / Q000821:virology; D014161:Transduction, Genetic; D019076:Transgenes
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; C483468:hemagglutinin, human influenza A virus; D049452:Green Fluorescent Proteins; D010735:Phosphoglycerate Kinase