Gene Therapy for HIV Infection
The National Institute of Allergy and Infectious Diseases (NIAID) supports 67 pre-clinical and clinical research projects in HIV gene therapy and related areas to develop new treatments to limit the virus' replication and destructive effects on the body. In FY 1994, NIAID devoted $27.7 million to this combined research effort.
HIV gene therapy involves inserting into human cells a gene that confers resistance to HIV infection and then infusing these altered cells into a person infected with HIV. Such therapy may help limit HIV replication and spread within the body and delay progression of HIV disease.
Five NIAID-supported gene therapy trials for HIV disease have been approved or are awaiting approval by the US Food and Drug Administration:
- A study involving inserting a gene for molecules called ribozymes into CD4+ T cells. Ribozymes can cut HIV's genetic material and may prevent infection of new cells. CD4+ T cells are the critical immune system cells targeted by HIV and depleted during HIV infection.
- A study to determine whether a modified form of and HIV protein called Rev, produced by a gene inserted into immune cells, can prevent the killing and depletion of the cells by competing with normal HIV Rev.
- A trial using infusions of HIV-infected patients' own CD8+ T cells grown to large numbers in the laboratory. In this study, the infused cells have a safety feature: they contain a suicide gene that allows investigators to eliminate the cells with certain drugs in the event of an adverse reaction. CD8+ T cells are important weapons in the body's immune defenses against viruses, including HIV.
- Two studies of the transfer of genetically altered immune cells from a healthy identical twin to his or her HIV-infected twin.
Other gene therapy trials supported by the private sector involve vaccines that incorporate a gene from HIV. As reported recently in media reports, these vaccines have been given to HIV-infected individuals, to boost their immune response to HIV. NIAID-funded investigators are pursuing similar strategies.
The future of HIV gene therapy may include the use of harmless viruses or non-viral agents such as tiny spheres called liposomes or gold particles to deliver protective genes into a patient's cells. NIAID supports these and other novel approaches to gene therapy through a number of programs, including the investigator-initiated RO1 grant mechanism, the National Cooperative Drug Discovery Groups for the Treatment of HIV Infection (NCDDG-HIV) and the Strategic Programs for Clinical Research on AIDS (SPIRAT). In addition, NIAID has established the Gene Therapy-HIV Working Group within the AIDS Clinical Trials Group to provide guidance to investigators on conducting clinical gene therapy research and to expedite the transition of preclinical research to human studies.
NIAID, a component of the National Institutes of Health, supports investigators and scientific studies at universities, medical schools, hospitals and research institutions in the United States and abroad aimed at preventing, diagnosing and treating such illnesses as AIDS, tuberculosis and asthma as well as allergies. NIH is an agency of the US Public Health Service, part of the US Department of Health and Human Services.Prepared by:
Office of Communications National Institute of Allergy and Infectious Diseases National Institutes of Health Bethesda, MD 20892
Public Health Service US Department of Health and Human Services