Dr. Ruth Ruprecht, scientist and director of the AIDS Research Program at Texas Biomed. Photo Courtesy of Texas Biomed
The National Institutes of Health have awarded scientists at Texas Biomedical Research Institute and collaborators at the Food and Drug Administration, UCLA and the University of Pennsylvania a $5 million grant over the next four years to study a combination of antiviral drugs and investigative AIDS vaccines aimed at treating infants and children affected by HIV. Dr. Ruth Ruprecht, a scientist and director of the Texas Biomed AIDS Research Program, is leading this study.
“Our goal is to determine whether these candidate vaccines, partnered with antiviral drugs, will not only completely suppress HIV replication in babies infected with HIV at birth, but will also induce such strong antiviral cellular immune defenses that the virus will not reemerge after all treatment is stopped,” Ruprecht says. “We will test our concepts in infant and neonatal rhesus monkeys. These primate models will allow us to assess whether the virus can be cleared from tissue reservoirs and whether long-lasting protective immunity has been generated by the combined treatment.”
A vaccine against HIV has still not been found. And, while current HIV therapies, called highly active anti-retroviral therapy (HAART), can suppress the virus, HAART is not a cure. HAART has proven effective at inhibiting and suppressing the replication of the virus, but once an HIV-infected person stops taking the drugs, the virus comes back.
Ruprecht explains, “We will provide HAART to infant monkeys to suppress the virus so the animals will no longer be viremic (show virus in the blood). Once the virus is shown to be suppressed, we will give them a combination rubella vaccine that has pieces of the SHIV (simian human immunodeficiency virus) inserted into the vaccine. This vaccine vector is so potent it induces a very strong immune response. Once HAART is stopped, our hope is that the vaccine-induced immune cells take over.”
Due to the prior vaccination, the immune system will be able to recognize viral proteins displayed on cells still infected with HIV that tell it the cell is infected. T cells in the body then recognize the infected cells and kill them.
“We are planning to induce strong killer cell activity,” Ruprecht says, “These cells will patrol the body and take out AIDS virus- infected cells that become activated once HAART has been stopped. We hope over time this patrolling and cell killing will shrink the virus reservoir and there will be fewer cells left in the body able to activate the virus.”
Ruprecht is coordinating this study with Ira Berkower, MD, PhD, Food and Drug Administration, who has performed the initial testing of the rubella vector-based vaccine, along with Yvonne J. Bryson, MD, chief of pediatric infectious diseases at UCLA, and Sarah J. Ratcliffe, PhD, associate professor of biostatistics at the Perelman School of Medicine, University of Pennsylvania who will provide biostatistical input to the study.
Ruprecht and her collaborators aim for this combined therapy approach to generate a functional cure, meaning it would rid the blood of the virus and eliminate the negative effects of HIV – without the need of continued HAART. At the same time, the combined approach could provide immunity against future HIV exposure.
“We are excited to launch this study and develop an attack plan against HIV that could both cure and provide a solid defense against further infection,” Ruprecht says.
This study is currently being funded by the National Institutes of Health National Institute of Allergy and Infectious Diseases.
Source: Texas Biomedical Research Institute