Indian scientists have achieved an important breakthrough in their efforts to develop a vaccine to prevent the deadly dengue. Supported by the Department of Biotechnology under the Ministry of Science & Technology, scientists at International Centre for Genetic Engineering and Biotechnology (ICGEB) in New Delhi have developed a non-infectious dengue vaccine from yeast.
Preliminary animal trials of the vaccine have yielded good results.
“Search for a dengue vaccine has been going on across the world for past several decades. We, at our centre, started experiments seven years ago. The new technology we have used, i.e. recombinant DNA technology, to develop the dengue vaccine is a breakthrough,” said Dr Navin Khanna, group leader of Recombinant Gene Products Group, ICGEB. The initial trials done on mice gave encouraging results.
The research team explored virus-like particles which can provide “robust immunity” against the vector-borne disease that is endemic to more than a hundred countries. “There are four closely related dengue viruses (DENVs) that cause this disease. A vaccine that can protect against all four DENVs is an unmet public health need,” said Dr Khanna.
Explaining the need to explore a new technology to develop the vaccine, he said: “Efforts to develop a live attenuated vaccine (a vaccine created by reducing the virulence of a pathogen but still keeping it viable) have encountered unexpected interactions between the vaccine viruses, raising safety concerns. This underscored the need to experiment with non-replicating vaccine options.”
Among the disadvantages of the vaccine developed by live attenuated technology is that it can cause severe complications in patients with low immunity.
The ICGEB scientists used the yeast ‘Pichia pastoris‘ to develop dengue virus-like particles. “Using recombinant DNA technology, we have created non-infectious dengue virus-like particles made of only the major DENV ‘envelope protein’ important for eliciting virus-specific immunity.
These virus-like particles elicit high levels of virus-neutralising antibodies which protected the mice significantly against lethal DENV challenge,” said Dr Khanna. “The encouraging data obtained for virus-like particles specific to one of the four DENVs warrant the development of virus-like particles specific to the remaining three DENV strains,” he added.