In a new study published in Science immunology, the scientists showed the effectiveness of vaccine against Zika, dengue and Hepatitis C viruses. They demonstrated that the natural killer cells (NK) can identify these viruses through a single receptor called KIR2DS2.
The outcomes of the study are very exciting and could change the way viruses are targeted by vaccines. However, the research is in the early stage, for which animal studies/clinical trials are required, said Salim Khakoo, Professor of Hepatology.
The vaccines stimulate the immune response against the virus (targets their protein coat) and enables body to fight off and identify these in the future. However, viruses can change their protein coat and make it hard to develop vaccine against them.
The research team from Southampton proved that the NK cells were able to target NS3 helicase protein (non-variable part of virus). This protein does not change unlike other proteins, hence enables the immune system to act on with the aid of NK cells.
"The NS3 helicase protein could be the key in unlocking the defence of lethal viruses that affect so many people around the world,” highlighted Professor Khakoo. It was revealed that all flaviviruses, including Hepatitis C, Zika virus, dengue virus, yellow fever virus, Japanese encephalitis virus contain a region within their NS3 helicase proteins that is identified by exactly the same KIR2DS2 receptor.
The researchers believed that by targeting NS3 helicase region, a new vaccine type based on NK cells could be introduced to protect people from these infections. In the study, the DNA from over 300 patients exposed to Hepatitis C virus was analyzed. It was noted that the KIR2DS2 receptor was involved in the virus decline.
The immune system targeted the NS3 helicase protein of the virus using the receptor and prevented its multiplication, researchers found. The same mechanism was proven to be the same for other viruses.
Further studies have to be carried out to prove that KIR2DS2+ NK cells are protective during acute flaviviral infections, and develop vaccine that targets the NK cells. A similar process could be used to target cancer, researchers believe.
"Cancer treatments that use the body's own immune system are becoming more common. Our findings present a completely new strategy for virus therapeutics which could be easily translated into the field of cancer. The next few years are going to be very exciting in this field," Professor Khakoo added.