Low autocrine interferon beta production as a gene therapy approach for AIDS: Infusion of interferon beta-engineered lymphocytes in macaques chronically infected with SIVmac251

BACKGROUND: The aim of this study was to evaluate gene therapy for AIDS based on the transduction of circulating lymphocytes with a retroviral vector giving low levels of constitutive macaque interferon β production in macaques chronically infected with a pathogenic isolate of SIVmac251. RESULTS: Two groups of three animals infected for more than one year with a pathogenic primary isolate of SIVmac251 were included in this study. The macaques received three infusions of their own lymphocytes transduced ex vivo with the construct encoding macaque IFN-β (MaIFN-β or with a vector carrying a version of the MaIFN-β gene with a deletion preventing translation of the mRNA. Cellular or plasma viremia increased transiently following injection in most cases, regardless of the retroviral construct used. Transduced cells were detected only transiently after each infusion, among the peripheral blood mononuclear cells of all the animals, with copy numbers of 10 to 1000 per 10(6 )peripheral mononuclear cells. CONCLUSION: Long-term follow-up indicated that the transitory presence of such a small number of cells producing such small amounts of MaIFN-β did not prevent animals from the progressive decrease in CD4(+ )cell count typical of infection with simian immunodeficiency virus. These results reveal potential pitfalls for future developments of gene therapy strategies of HIV infection

Cellular and Gene Therapy for Major Histocompatibility Complex Class II Deficiency

Major histocompatibility complex (MHC) class II deficiency is a primary immunodeficiency. Lentiviral vectors are used for gene therapy in a mouse model of this disease. In addition, by a direct genetic correction approach, a diagnostic test to determine which of the four MHC II genes is defective in new MHC II-deficiency patients has been optimized.</p

Direct genetic correction as a new method for diagnosis and molecular characterization of MHC class II deficiency

Major histocompatibility complex class II (MHCII) deficiency is a primary immunodeficiency resulting from defects in one of four different MHCII-specific transcription factors-CIITA, RFX5, RFXAP, and RFXANK. Despite this genetic heterogeneity, the phenotypical manifestations are homogeneous. It is frequently difficult to establish a definitive diagnosis of the disease on the basis of clinical and immunological criteria. Moreover, the phenotypical homogeneity precludes unambiguous identification of the regulatory gene that is affected. Identification of the four genes mutated in the disease has now allowed us to develop a rapid and straightforward diagnostic test for new MHCII-deficiency patients. This test is based on direct correction of the genetic defect by transduction of cells from patients with lentiviral vectors encoding CIITA, RFXANK, RFX5, or RFXAP. We have validated this approach by defining the molecular defects in two new patients. The RFXANK vector restored MHCII expression in a T cell line from one patient. The RFXAP vector corrected primary cells (PBL) from a second patient. Molecular analysis confirmed the presence of homozygous mutations in the RFXANK and RFXAP genes, respectively. Direct genetic correction represents a valuable tool for the diagnosis and classification of new MHCII-deficiency patients