'Sleepy' immune system might fight HIV
A Manitoba AIDS scientist, who has spent 25 years trying to unlock the mystery of HIV-resistant sex workers in Kenya, says a reduced immune system might actually be the best defence against the disease.
This insight, if proven, could turn billions of dollars in global HIV vaccine research on its head.
And Dr. Frank Plummer and his research team hope their discovery will lead to the creation of an HIV vaccine gel for millions of women.
When a person becomes infected with HIV, the virus goes after the immune system, breaking it down and infecting the cells.
So Plummer and his team studied what happens if an immune system doesn't fight back, doesn't give the virus anything to feed off.
The secret is trying to make an immune system more "sleepy" to HIV so the deadly virus never takes hold, said Plummer, scientific director of the National Microbiology Laboratory in Winnipeg.
The sex trade workers he's studied in Africa since 1985 do this naturally.
"One of the signature characteristics of these (women) is that they have what we call a quiescent immune, or if you like, a 'sleepy immune' system," Plummer told an audience attending a TedX Manitoba conference in Winnipeg on Tuesday.
Plummer and his team just won a five-year $680,000 federal grant to develop a microbicidal gel that will try to copy this protective effect.
The discovery is the result of years of tracking sex trade workers in Nairobi slums who have defied the odds and avoided HIV. Many of the women live in areas with 50 per cent HIV infection rates, where their sex work exposes their bodies to the virus many times a day, and over many years.
Salome Simon is an example. When she appeared in a CBC News The National documentary in 2006, she had been doing sex work uninfected for more than two decades.
"I was very happy to find out that I am resistant. I have seen many of my friends die, but I thank God that I don't have HIV," Simon told CBC News at the time through a translator.
Plummer believes women like her have a natural protection to HIV because their immune systems are so inactive in response to the virus.
Normally, a women's immune system reacts to HIV by sending in immune cells to counter the virus and stimulate inflammation in the vagina. This, unfortunately, provides avenues for viral infection.
But this wasn't happening in the Kenyan women.
"What we found is that [the sex trade workers] secrete these specific proteins which counter inflammation. This was counter-intuitive," says Dr. Adam Burgener, a University of Manitoba microbiologist who travels back and forth to Nairobi for the research.
"We would've thought there would be lots of inflammation and that they would mount a very strong response during sex work. But it's the opposite — they have a very subdued immune system," says Burgener.
Until now, people involved in vaccine development have focused on "jazzing up" the immune system, making it very active, said Plummer.
"And if our work is correct … that may not be the best thing to do."
Pharmaceutical giant Merck found out the hard way. It invested heavily in a vaccine to boost immune systems, only to find out in its clinical trials in 2007 that the approach only made HIV infection worse.
So, the idea that a Manitoba-grown idea to conquer AIDS has researchers here, like Burgener, losing sleep.
"It's very exciting. I have difficulty sleeping on Sunday nights because I'm excited about the work week and what we have to accomplish in order to get into testing."