The apparent success of a vaccine against the highly pathogenic Simian Immunodeficiency Virus (SIV) may offer promise for a vaccine that protects humans against HIV.
The novel vaccine used in the proof-of-concept study on rhesus macaques was based upon Heat Biologics' Immune Pan-Antigen Cytotoxic Therapy (ImPACT) technology that transforms cells so that they secrete the heat shock protein gp-96. The research, conducted at the Advanced Bioscience Laboratories in Rockville, MD, and published in Journal of Immunology (sub. req.), was funded primarily by a grant from the National Institutes of Health (NIH).
The vaccine offered significant protection to rhesus macaques from mucosal infection by SIV. The researchers vaccinated 36 macaques in total, split evenly into three cohorts. Cohort 1 received cells secreting gp96SIVIg carrying SIV peptides, and Cohort 2 received cells secreting gp96SIVIg and recombinant envelope protein SIV-gp120. Cohort 3 received cells secreting gp96-Ig with no SIV Ags. The results showed that the macaques in Cohort 2 were protected from infection, displaying a highly significant 73% reduced risk for viral acquisition after seven rectal challenges with SIV. According to the press release, these results are among the best prophylactic protection ever seen against SIV.
“Vaccine-induced protection against infection by HIV or SIV has been limited. And while HIV can be controlled with an intensive drug regimen, the required medication is life-long and may have unpleasant side effects,” said Dr. Eckhard Podack, MD, PhD, professor and chair of the Department of Microbiology and Immunology at the University of Miami Miller School of Medicine in a press release. “To our knowledge, with this study we achieved a degree of protection against SIV that is among the best ever seen and invites further development to achieve full protection. The findings are significant, suggesting that an ImPACT-based vaccine will be able to provide complete protection against infection with HIV.”
“This research further validates the significant potential that the ImPACT therapeutic vaccine platform holds,” said Jeffrey Wolf, president and CEO, Heat Biologics in a press release. “It is an exciting addition to Dr. Podack’s groundbreaking work with the ImPACT Therapy which has already generated encouraging results in the treatment of other life-threatening diseases."
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