RESUMO
Several clinical studies of gene-modified T cells have shown limited in vivo function of the cells, immunogenicity of the transgene, and lack of a selective advantage for gene-modified T cells. To address these problems, we developed a lentiviral vector (LV) that provides a selectable, proliferative advantage and potentially decreases immunogenicity for transduced T cells. The bicistronic vector expressed two genes linked with an internal ribosomal entry site. One gene is a variant of the inosine monophosphate dehydrogenase 2, inosine monophosphate dehydrogenase (IMPDH(IY)), conferring resistance to the immunosuppressive drug mycophenolate mofetil (MMF). The other is a suicide gene, herpes simplex virus thymidine kinase (HSV-TK), rendering proliferating cells sensitive to ablation with ganciclovir, fused to the selectable transmembrane marker DeltaCD34 (DeltaCD34/TK). Cells transduced with LV-DeltaCD34/TK.IMPDH(IY) were efficiently enriched by immunomagnetic selection for CD34, proliferated in 0.5-5 microM MMF, and were killed by 0.5-25 microg ml(-1) ganciclovir. We demonstrate efficient selection and killing of gene-modified cells and suggest LV-DeltaCD34/TK.IMPDH(IY)-transduced T cells could be used to facilitate allogeneic hematopoietic cell engraftment. The expression of IMPDH(IY) would allow in vivo selection with MMF, and DeltaCD34/TK expression would allow rapid and safe elimination of transduced T cells if graft-versus-host disease developed.
Assuntos
Genes Transgênicos Suicidas , Terapia Genética/métodos , Vetores Genéticos/genética , Herpesvirus Humano 1/enzimologia , IMP Desidrogenase/genética , Linfócitos T , Timidina Quinase/genética , Antivirais/uso terapêutico , Proliferação de Células , Clonagem Molecular , Resistência a Medicamentos , Ganciclovir/uso terapêutico , Engenharia Genética , Vetores Genéticos/administração & dosagem , Doença Enxerto-Hospedeiro/prevenção & controle , Transplante de Células-Tronco Hematopoéticas , Humanos , IMP Desidrogenase/metabolismo , Separação Imunomagnética/métodos , Imunossupressores/farmacologia , Células K562 , Ácido Micofenólico/análogos & derivados , Ácido Micofenólico/farmacologia , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/virologia , Transdução Genética/métodos , Transplante HomólogoRESUMO
Ameloblastomas are common in Niger. Their main risk is recurrence, which nearly always follows inadequate surgery: these tumors require radical excision followed with mandibular graft. A preoperative diagnosis is therefore indispensable. X-ras are non-specific. In Niger, the danger of osteomyelitis makes surgical biopsies dangerous. The attention is brought to the existence of gum lesions in 8 cases of ameloblastoma in Nigerian patients. Their biopsy may provide the diagnosis in quick and safe conditions.
