By Avigayil Kadesh
If you get sick with flu, it’s because the virus found a way to neutralize the “natural killer” (NK) cells of your immune system. When working at full capacity, NK cells recognize and destroy influenza-virus-infected cells before they can spread throughout your body.
Israeli doctoral student Yotam Bar-On, 30, was determined to find out how the mechanism works and then formulate a new drug to stop flu in its tracks.
Existing antiviral medications for flu sufferers are not always effective, as they can cause the virus to work even harder at fighting the immune system, leading to resistant flu strains.
This can be a matter of life and death. Several flu pandemics over the past decade have left a deadly legacy. Recently, a new avian influenza strain (H7N9) that emerged in China killed six people in one month.
“A few years ago, my supervisor, Prof. Ofer Mandelboim, discovered that NK cells are important in fighting flu infection,” Bar-On says. Mandelboim is a professor of immunology at the Institute for Medical Research Israel Canada (IMRIC) at the Hebrew University Faculty of Medicine.
“However, when we infected mice with influenza virus, we found that the virus can manipulate the NK cells and evade getting killed. The NK function is not 100 percent because the influenza fights back.”
Sets the tone for smarter drugs
As they reported in an article published in the journal Cell Reports
, Bar-On and Mandelboim found out that the flu virus uses a protein called neuraminidase as a weapon to weaken the power of NK cells by half. Many of the infected mice in their experiment died from influenza because of this phenomenon.
So they decided to target neuraminidase.
“Most interestingly, when we inhibited the neuraminidase we noticed the NK worked better, and the mice actually recovered from the flu,” says Bar-On. “So we proved the ability to defend against the influenza virus by inhibiting this protein.”
Bar-On says their discovery “sets the tone for developing new treatments” to boost the natural immune system.
“Right now, existing drugs work to inhibit a different protein in the flu virus to inhibit the spread of the virus, but their disadvantage is that the virus can mutate and evade the effects of the drug,” Bar-On explains. “You then get a resistant strain.”
He says that a drug that would inhibit neuraminidase would be much harder for the virus to overcome. “Under the supervision of Prof. Mandelboim, I am now working on a more practical approach to develop such a drug,” Bar-On reveals.