Researchers have identified the following cell-based approaches to treat infectious diseases.
- Using T cells to seek, find, and kill HIV-infected cells.
- T cells are also being engineered to produce a material such as an antiviral RNA or an enzyme (zinc finger nuclease) that blocks virus infection with the intent to help patients maintain a sufficient level of T cells for immune functions.
Stem-cell Based Approaches
Genetic manipulation of the blood progenitor cell or progenitors of T cells, using genes known to block replication and infection of viruses such as HIV, have also undergone testing in HIV/AIDS patients using bone marrow transplantation. If successful, this method would allow a patient to make T cells that are resistant to HIV infection. This approach remains early in its development and is limited by our understanding of how to establish safe and durable engraftment of modified progenitor cells.
Genetic Vaccines
Vaccines which use gene transfer techniques include DNA vaccines, recombinant viral vaccines, and RNA-based dendritic cell vaccines. Each of these introduce viral encoded sequences for immunologically important anatigens which could contribute to immunity. Although no genetic vaccine has been approved for human use, this is an active area in which several vaccines against infections agents are being tested in humans.
Other Approaches
Use of genetic vectors for rapid introduction of protective proteins have been shown to be feasible in animal models, but have yet to be tested in humans.
Gene Therapy
Gene therapy is being investigated as an alternative treatment for a wide range of infectious diseases that are not amenable to standard clinical management. Approaches to gene therapy for infectious diseases can be divided into three broad categories: (i) gene therapies based on nucleic acid moieties, including antisense DNA or RNA, RNA decoys, and catalytic RNA moieties (ribozymes); (ii) protein approaches such as transdominant negative proteins and single-chain antibodies; and (iii) immunotherapeutic approaches involving genetic vaccines or pathogen-specific lymphocytes. It is further possible that combinations of the aforementioned approaches will be used simultaneously to inhibit multiple stages of the life cycle of the infectious agent.
Gene therapy holds considerable potential for the treatment of both hereditary genetic disorders and infectious diseases.
