A vaccine discovered and tested by an international team led by The Ohio State University research scientist Abhay Satoskar, MD, PhD, could lead to the development of a novel safe, effective and affordable vaccine for preventing COVID-19. It holds great promise for the prevention of other co-endemic viral and bacterial infections.
“Several vaccines for SARS-CoV-2 are currently under development. However, it is not clear whether these vaccines will be affordable and have community compliance in developing countries in the long term,” says Dr. Satoskar. While common in the U.S., the use of vaccines to prevent flu viruses is limited in developing countries in Africa, Asia and South America with undetermined effectiveness in long-term protection.
“The spike (S) protein on SARS-CoV-2, which is glycosylated, is a promising candidate for a vaccine, as it is indispensable for viral entry into the host cells through binding to angiotensin-converting enzyme 2 expressed on the cell surface,” explains Dr. Satoskar. “A straightforward approach for vaccine development could be to use recombinant S protein (rS) produced in bacteria with an adjuvant such as alum, which induces a strong antibody response. However, bacteria-produced rS protein will be non-glycosylated and, therefore, could be poorly immunogenic.”
For the past several years, Dr. Satoskar has been developing a vaccine for another disease—leishmaniasis—that he believes can be modified to produce a glycosylated S antigen and immunity to the novel coronavirus. “Our data show that immunization with LmCen-/- induces a robust antigen-specific antibody as well as cell mediated immune responses—even in the absence of an adjuvant,” he explains. “In the present project, we propose to test the hypothesis that vaccination with genetically engineered eukaryote LmCen-/- producing glycosylated S antigen will induce robust and sustained immunity against SARS-CoV-2 as well as leishmaniasis.”
The vaccine LmCen-/- has proven effective in previous studies led by Dr. Satoskar using animal models as a vaccine against leishmaniasis, a parasitic and potentially deadly disease found in parts of the tropics, subtropics, southern Europe and, recently, in the U.S. Dr. Satoskar’s team will soon begin testing the antigen in humans, thanks to a $4.2 million grant from the National Institutes of Health.
Dr. Satoskar, professor in the Department of Pathology at The Ohio State University College of Medicine, has spent much of his 30-year career studying leishmaniasis, which spreads from sand flies to humans and infects approximately 12 million people worldwide with 400,000 deaths each year, placing it second only to malaria in its impact and resistance to treatment. The antigen LmCen-/- developed by Dr. Satoskar’s team as a vaccine for leishmaniasis has been determined to be safe and effective in pre-clinical animal studies, according to Food and Drug Administration’s Guidance and Good Manufacturing Practices. It is slated for testing in clinical trials with humans beginning in 2021.
As a proof of concept, the team has successfully developed a genetically engineered LmCen-/- expressing hepatitis B surface antigen in preliminary studies. “Our studies could not only lead to development of a novel vaccine against SARS-CoV-2 for deployment in resource poor developing countries,” he says, “but will also provide a foundation for using LmCen-/- platform to develop vaccine against other co-endemic viral and bacterial infections, such as the human papillomavirus, which is responsible for the high incidence of cervical cancer in such countries.”