The Wistar Institute in Philadelphia has announced positive results from preclinical testing of a synthetic DNA vaccine for SARS-CoV-2, developed in collaboration with Inovio Pharmaceuticals, Inc., of Plymouth Meeting, Pa., and other scientists. Wistar, an international biomedical research leader, made the announcement on May 20 with a report of the results published in Nature Communications. The report focuses on immune studies in animals, which show induction of functional antibody responses and T-cell responses following immunization.

With development of a vaccine a top priority, and once the viral genome became available on January 11, 2020, the Wistar-Inovio team immediately began working to design and develop a new vaccine. Their work was based largely on their previous experience creating a synthetic DNA vaccine against the related coronavirus that causes Middle East Respiratory Syndrome (MERS).

A group led by David B. Weiner, Ph.D., Wistar executive vice president, director of the Vaccine & Immunotherapy Center (VIC) and W.W. Smith Charitable Trust Professor in Cancer Research, focused on rapid development of a synthetic DNA-based vaccine targeting the major surface antigen Spike protein (S) of SARS-CoV-2 into preclinical studies. The vaccine candidate, INO-4800, was advanced to phase 1 clinical testing in 10 weeks.

“We focused on both assay development and vaccination studies to test if immune responses induced by the vaccine in laboratory animals were functional against the virus. Our focus was the induction of immune responses that could in concept make it difficult for SARS-CoV-2 to have a home in the human body,” said Weiner, co-senior author of the publication. “The vaccine was designed leveraging our synthetic DNA technology, which has a set of conceptual advantages including accelerated clinical development built on a conceptually safe, non-live, simple platform that has scalable manufacturing and temperature stability. The vaccine-induced antibodies in vaccinated animals were of sufficient quantity and quality to block interaction of the virus with its receptor, which is its doorway into infecting the body, and were present in the lungs, a place where immunity is very important. The vaccine also induced T-cell function, which is critical for clearing viral infections from the body. These are indications that the immunity it induced might provide no escape for the SARS-CoV-2 virus. We are looking forward to additional studies and examining data from the ongoing clinical trial.”

The development team includes Wistar VIC investigators Daniel Kulp, Ph.D., Kar Muthumani, Ph.D., and Ami Patel, Ph.D., who is a shared first author in the paper.

“While this candidate continues its journey as a potential vaccine against COVID-19, we are continuing our work in the lab to gather more information on the vaccine’s performance in small and larger animals,” said Patel, who is a research assistant professor at Wistar. “We will further characterize antibody functionality, cellular responses, and the ability of INO-4800 to mediate protection of animals against viral challenge.”

Wistar has also launched the Wistar Coronavirus Discovery Fund to accelerate the full range of COVID-19 research projects its scientists are undertaking to advance vaccines, diagnostics and therapeutics and create effective solutions that can be rapidly delivered to the public. Learn more at