On Sept. 3, 2014, Oregon Health & Science University (OHSU) announced it had been awarded a $25 million grant from the Bill & Melinda Gates Foundation to advance work on a promising vaccine candidate that may someday prevent or cure infection with HIV, the virus that causes AIDS.

The grant, awarded to a team of scientists at OHSU’s Vaccine and Gene Therapy Institute led by Louis Picker, M.D., was among the largest philanthropic grants OHSU had ever received.

Last year, more than 35 million people throughout the world were living with HIV, the virus that causes AIDS, according to the World Health Organization. While the annual number of new HIV infections has declined in recent years, an estimated 2.1 million people were newly infected with the virus last year.

And while antiretroviral drug therapy has also steadily decreased the number of AIDS-related deaths in recent years, an estimated 1.5 million people still died from AIDS last year, according to the WHO.

The work of Picker and his colleagues focuses on a possible vaccine that shows promise in not only preventing the HIV virus from establishing infection in exposed, uninfected individuals, but also holds the hope of eliminating the virus from people who are already infected.

Picker and his colleagues published research in the journal Nature last year that detailed how their vaccine candidate protected monkeys given the simian immunodeficiency virus — or SIV, the non-human primate version of HIV. The vaccine stopped the infection from spreading and then cleared it from the bodies of half of the monkeys it was tested on.

The Picker team’s approach involves the use of cytomegalovirus, or CMV, a virus that is already carried by most humans and is generally harmless. The researchers discovered, as they reported in Nature, that engineering CMV to express SIV proteins had a unique effect. This modified version of CMV was able to generate and indefinitely maintain so-called “effector memory” T cells that target SIV and are capable of searching out and destroying SIV-infected cells.