REVM10-EXPRESSING T-CELLS DERIVED IN-VIVO FROM TRANSDUCED HUMAN HEMATOPOIETIC STEM-PROGENITOR CELLS INHIBIT HUMAN-IMMUNODEFICIENCY-VIRUS REPLICATION

A key feature of the pathogenesis of human immunodeficiency virus type 1 (HIV-1) infection is the gradual loss of CD3-positive T cells. A nu mber of gene therapy strategies have been designed with the intent of inhibiting HIV replication in mature T cells. As T cells are products of hematolymphoid differentiation, insertion of antiviral genes into h ematopoietic stem cells could serve as a vehicle to confer long-term p rotection in progeny T cells derived from transduced stem cells. One s uch ''cellular immunization'' strategy utilizes the gene coding for th e HIV-1 rev trans-dominant mutant protein RevM10 which has been demons trated to inhibit HIV-1 replication in T-cell lines and in primary T c ells. In this study, we used a Moloney murine leukemia virus-based ret rovirus encoding a bicistronic message coexpressing RevM10 and the mur ine CD8-alpha' chain (Lyt2). This vector allows rapid selection of tra nsgene-expressing cells as well as quantitation of transgene expressio n. We demonstrate that RevM10-transduced CD34-enriched hematopoietic p rogenitor-stem cells (HPSC) isolated from human umbilical cord blood o r from granulocyte colony-stimulating factor-mobilized peripheral bloo d can give rise to mature thymocytes in the SCID-hu thymus/liver mouse model. The phenotypic distribution of HPSC-derived thymocytes is norm al, and expression of the transgene can be detected by how cytometric analysis. Moreover, we demonstrate that RevM10 can inhibit HIV replica tion in T cells derived from transduced HPSC after expansion in vitro. This is the first demonstration of anti-HIV efficacy in T cells deriv ed from transduced human HPSC.