According to Dr. June, "the potential clinical importance of our finding is that this form of activation could lead to a class of drugs to prevent CCR5 expression in all individuals and eventually provide new vaccine and therapy strategies."
CCR5, identified in 1996, serves as a coreceptor for viruses typically found in the early, asymptomatic stages of HIV-1 infection. Another coreceptor, termed CXCR4/Fusin, discovered by Edward Berger and colleagues in 1996, is used by viruses obtained from individuals in the late stages of HIV- 1 infection, or by viral isolates that have been adapted to grow in T cell lines in the laboratory. While stimulation of the CD28 receptor does not prevent expression of CXCR-4/Fusin on the T cell surface, and hence infection by late stage HIV- 1 strains, the researchers are optimistic that this result may lead to other strategies by which coreceptor expression can be regulated. Formerly, it was believed that activation and growth of T cells necessarily lead to HIV- 1 susceptibility. These studies demonstrate that expression of coreceptors can be regulated in activated, growing T cells. It is likely that these observations could lead to the development of new therapeutic options for patients with HIV infection, as well as other immune deficiencies and cancer. Patients could receive infusions of CD4+ T cells, similar to blood bank transfusion procedures, thus possibly preventing the deterioration of immune function that accompanies HIV infection. This procedure could also have therapeutic utility for symptoms that result from HIV infection. A pilot clinical trial to test the safety and feasibility of this approach is currently underway.
The U.S. Military HIV Research Program is carried out under a cooperative agreement between the Henry M. Jackson Foundation for the Advancement of Military Medicine and the U.S. Army Medical Research and Materiel Command.
The Henry M. Jackson Foundation is a private, not-for-profit organization chartered by Congress in 1983 to support medical research and education throughout the military medical community. The Foundation has collaborated on the U.S. Military HIV Research Program since its inception in 1988.