University Of Miami Researchers Believe They Have Developed A Promising AIDS Vaccine

Researchers at the University of Miami believe they have made a significant breakthrough in the quest for an AIDS vaccine.

A research team at the University of Miami say they have developed a vaccine that triggers an immune system response strong enough to kill a model AIDS virus in mice.

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Geoffrey W. Stone, a UM assistant professor of microbiology and immunology who led the research study published in February’s Journal of Virology, says the vaccine is still in the early stages of development but his team has already had some very dramatic results.”

Stone’s research team has taken a different approach to the standard vaccines that introduce a virus protein that triggers an immune system response. Instead, the UM vaccine uses a more targeted approach.

What we have done is we’ve attached it on to the guided missile that brings it to the bad cells but brings it to the good cells, cells called dendrite cells, and helps those cells do a better job,” Stone told WSVN.

The vaccine targets specific cells, delivering an important warning to the immune system. “These cells are very sensitive to danger signals, the things that happen when you get a cold. These cells get activated. If you don’t activate them, they don’t work well,” said Stone.

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According to the University of Miami press release:

The research, conducted at the Miller School’s Miami Center for AIDS Research, is being led by Geoffrey W. Stone, Ph.D., assistant professor of microbiology and immunology, and the results are published in the February 2014 issue of the Journal of Virology. The key finding is that the vaccine developed by Stone’s team, when targeted to a unique receptor in the immune system, can generate unprecedented T cell responses to HIV. The receptor involved is called CD40, and the vaccine uses a special form of its natural binding protein, CD40 ligand (CD40L), to enable important immune cells called dendritic cells to detect the presence of HIV proteins.

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Dendritic cells are the gatekeepers of the immune system. They collect and process foreign proteins, known as antigens, and then alert the rest of the immune system to the invader. An essential step in this process is that the dendritic cells must become activated through the CD40 receptor.

Stone and his collaborators have found that directly coupling the foreign protein antigen to a special form of CD40 ligand leads to extraordinarily strong CD8+ T cell responses in mice. In the case of an HIV protein, the vaccinated mice were able to completely fend off infection by more than 10 million model viruses containing the HIV protein antigen. This type of extreme immune protection, called sterilizing immunity, is rarely seen in vaccine studies.

“The key to the vaccine’s effectiveness is that it contains a new form of CD40 ligand connected to the foreign protein antigen,” explained Stone. “This means that the dendritic cell both receives the antigen and is activated by its CD40 receptor at the same time.”

The research offers hope for the development of vaccines for other diseases, as well. Large numbers of CD8+ T cells can also protect against influenza, malaria and cancer, but no current vaccines generate enough CD8+ T cells to be effective.
“Vaccine-induced protection has been very difficult to achieve,” said Stone. “This new vaccine design takes us to another level in stimulating the immune system to produce CD8+ T cells. The next steps will be to test the vaccine in monkeys, and then in humans.”

The study was supported by the National Institute of Allergy and Infectious Diseases and the National Institute on Drug Abuse.