New ‘OPAL Therapy’ Presents Simple, Cost-effective Method Of Treating HIV Infection
Australian researchers have unveiled a new immunotherapy technique to help prevent the progression from HIV infection to AIDS. Details of the simple, cost-effective technique are published May 2nd in the open-access journal PLoS Pathogens.
There is an overwhelming need for effective immunotherapies for HIV, as current therapies are expensive, impractical, and often highly toxic. The authors, led by Professor Stephen Kent, propose a technique named OPAL therapy–Overlapping Peptide-pulsed Autologous CeLls–a reinfusion of fresh blood cells incubating with overlapping SIV peptides. The OPAL technique was successfully tested in animal trials for stimulation of immunity, control of virus levels, and prevention of AIDS.
Vaccination diminished the levels of virus 10-fold lower than in controls, and was shown to be durable for over one year past initial vaccination. Therefore, viral replication was shown to be prolonged and more manageable, resulting in fewer deaths from AIDS.
The study is the result of collaboration among researchers from the University of Melbourne, the National Serology Reference Laboratory, and the University of New South Wales. The researchers plan to conduct future OPAL-therapy clinical trials in HIV-infected humans.
PLoS Pathog 4(5): e1000055. doi:10.1371/journal.ppat.1000055
Control of Viremia and Prevention of AIDS following Immunotherapy of SIV Infected Macaques with Peptide-Pulsed Blood.
De Rose R, Fernandez CS, Smith MZ, Batten CJ, Alcaˆntara S, et al. (2008)
Effective immunotherapies for HIV are needed. Drug therapies are life-long with significant toxicities. Dendritic-cell based immunotherapy approaches are promising but impractical for widespread use. A simple immunotherapy, reinfusing fresh autologous blood cells exposed to overlapping SIV peptides for 1 hour ex vivo, was assessed for the control of SIVmac251 replication in 36 pigtail macaques. An initial set of four immunizations was administered under antiretroviral cover and a booster set of three immunizations administered 6 months later. Vaccinated animals were randomized to receive Gag peptides alone or peptides spanning all nine SIV proteins. High-level, SIV-specific CD4 and CD8 T-cell immunity was induced following immunization, both during antiretroviral cover and without. Virus levels were durably ~10-fold lower for 1 year in immunized animals compared to controls, and a significant delay in AIDS-related mortality resulted. Broader immunity resulted following immunizations with peptides spanning all nine SIV proteins, but the responses to Gag were weaker in comparison to animals only immunized with Gag. No difference in viral outcome occurred in animals immunized with all SIV proteins compared to animals immunized against Gag alone. Peptide-pulsed blood cells are an immunogenic and effective immunotherapy in SIV-infected macaques. Our results suggest Gag alone is an effective antigen for T-cell immunotherapy. Fresh blood cells pulsed with overlapping Gag peptides is proceeding into trials in HIV-infected humans.