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Experimental Vaccine Helps Suppress Virus in People with HIV

, by San Francisco AIDS Foundation

While the search continues for a vaccine to prevent HIV infection, a new report highlights the promise of a therapeutic vaccine—one used to control the virus in people already living with HIV.

In their study, Felipe García from the University of Barcelona and colleagues employed a vaccine using specialized white blood cells, called dendritic cells, that had been taken from study participants and “pulsed” with inactivated HIV. (A control group received a vaccine using dendritic cells that had not been exposed to the virus.)

Dendritic cells are important in the body’s immune response; they function as sentinels, patrolling the body and “reporting back” to T cells (another essential player in the immune response) when they find viruses, bacteria, and toxins. Dendritic cells alert T cells that the body has been infected or injured and present antigens—molecules from the surfaces of viruses and bacteria—to the T cells. The T cells in turn recognize these antigens and can then launch an immune response designed to target the specific virus or harmful bacteria that has entered the body.

“Vaccination was feasible, safe, and well tolerated and shifted the virus/host balance,” the study authors note. Twelve weeks after receiving the pulsed vaccine and stopping antiretroviral therapy, 55% of participants saw a significant drop in their viral load and an increase in their T cell response to HIV. Although the effects diminished over 48 weeks, the study offers proof of concept, the researchers explain, and support further efforts to study therapeutic vaccines “as an alternative to [antiretroviral therapy] for life.”

In a video accompanying the publication, lead researcher García observes that the study “opens the possibility that a therapeutic vaccine could be used as a strategy to obtain or reach a functional cure”—that is, a cure that does not eradicate HIV from the body but does allow people with the virus to stop taking antiretroviral drugs without further disease progression. “This is just the first step, but we think that in collaboration with other groups…we could reach this objective” in the near future, he concludes.

You can click here to watch the full video; the article abstract is available here. Although the full text of the journal article is not available to non-subscribers, you can get the study details from Liz Highleyman’s summary piece, excerpted below and available in full at HIVandHepatitis.com.

Dendritic Cell Therapeutic Vaccine Helps Immune Cells Control HIV Replication

January 15, 2013

By Liz Highleyman

A therapeutic vaccine made from dendritic cells primed with heat-inactivated HIV stimulated immune cells to mount a response against the virus without it infecting and killing them, according to a study described in the January 2, 2013, issue of Science Translational Medicine.

Many HIV vaccine candidates are intended to prevent initial HIV infection, but therapeutic vaccines are designed to inhibit viral activity after infection, with the aim of halting disease progression and potentially allowing people to reduce or stop their antiretroviral therapy (ART)….

Click here to read the full summary on HIVandHepatitis.com.

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