HealthDay News — A HIV vaccine currently in development can ramp up the body’s immune system, boosting the response to highly-active antiretroviral therapy, preliminary research data published in Retrovirology suggests.

“HIV-1 persistence in reservoirs is associated with immune activation and T and B cell dysfunction, which represent the unmet needs of highly-active antiretroviral therapy (HAART) and are the cause of increased patients’ morbidity and mortality due to non-AIDS related diseases,” wrote Barbara Ensoli, MD, PhD, director of the National AIDS Center at the National Institute of Health in Rome, and colleagues.

To evaluate the effectiveness of the experimental vaccine, the investigators conducted a phase II clinical trial that injected 168 HIV-positive patients with biologically active HIV-1 vaccine containing either 7.5 µg or 30 µg of the Tat protein three to five times monthly for 48 weeks. The patients also continued on HAART. The researchers tracked the patients for up to 144 weeks, or nearly 3 years.

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The vaccine was safe and well tolerated, inducing anti-Tat antibodies in 79% of patients, with the highest frequency and durability in the Tat 30 µg groups when given three times. Vaccination also promoted a durable and significant restoration of T, B, natural killer cells, and CD4+ and CD8+ central memory subsets.

A significant reduction of blood proviral DNA was seen after week 72, and reached a predicted 70% decay after three years from vaccination with a half-life of 88 weeks.

“Anti-Tat immune responses are needed to restore immune homeostasis and effective anti-viral responses capable of attacking the virus reservoir,” concluded the researchers.

“Thus, Tat immunization represents a promising pathogenesis-driven intervention to intensify HAART efficacy.”


  1. Ensoli B et al. Retrovirology. 2015; doi: 10.1186/s12977-015-0151-y