RESUMO
HIV-1 infection requires the presence of the CD4 receptor on the target cell surface and a coreceptor, predominantly CC-chemokine receptor 5 (CCR5). It has been shown that individuals who are homozygous for a defective CCR5 gene are protected from HIV-1 infection. A novel self-inactivating lentiviral vector LVsh5/C46 (Cal-1) has been engineered to block HIV-1 infection with two viral entry inhibitors, conferring resistance to HIV-1 infection from both CCR5 and CXCR4 tropic strains. Cal-1 encodes a short hairpin RNA (sh5) to downregulate CCR5 and C46, an HIV-1 fusion inhibitor. Gene therapy by Cal-1 is aimed at transducing CD4+ T cells and CD34+ hematopoietic stem/progenitor cells in an autologous transplant setting. Pre-clinical safety and efficacy studies in vitro and in vivo (humanized mouse model and nonhuman primates) have shown that Cal-1 is safe with no indication of any toxicity risk and acts to decrease viral load and increase CD4 counts. Two clinical trials are underway using Cal-1: a phase I/II study to assess safety and feasibility in an adult HIV-1-positive population not on antiretroviral therapy (ART); and a second Fred Hutchinson Investigator Initiated phase I study to assess safety and feasibility in adults with HIV-1-associated non-Hodgkin or Hodgkin lymphoma.
Assuntos
Terapia Genética/métodos , Infecções por HIV/terapia , HIV-1/fisiologia , Fusão de Membrana , Receptores CCR5 , Receptores de HIV/antagonistas & inibidores , Proteínas Recombinantes de Fusão/biossíntese , Adulto , Animais , Terapia Biológica/métodos , Antagonistas dos Receptores CCR5 , Contagem de Linfócito CD4 , Ensaios Clínicos como Assunto , Regulação para Baixo , Infecções por HIV/genética , Infecções por HIV/virologia , HIV-1/genética , Células-Tronco Hematopoéticas , Humanos , Receptores CCR5/biossíntese , Receptores CXCR4 , Proteínas Recombinantes de Fusão/genética , Carga ViralRESUMO
Human immunodeficiency virus type 1 (HIV-1) infection of target cells requires CD4 and a co-receptor, predominantly the chemokine receptor CCR5. CCR5-delta32 homozygosity results in a truncated protein providing natural protection against HIV infection-this without detrimental effects to the host-and transplantation of CCR5-delta32 stem cells in a patient with HIV ("Berlin patient") achieved viral eradication. As a more feasible approach gene-modification strategies are being developed to engineer cellular resistance to HIV using autologous cells. We have developed a dual therapeutic anti-HIV lentiviral vector (LVsh5/C46) that down-regulates CCR5 and inhibits HIV-1 fusion via cell surface expression of the gp41-derived peptide, C46. This construct, effective against multiple strains of both R5- and X4-tropic HIV-1, is being tested in Phase I/II trials by engineering HIV-resistant hematopoietic cells.