Research Collaboration Developing SARS-CoV-2 Vaccine Based on Horsepox Virus

A New York based biopharmaceutical company announced a strategic collaboration to support the development of the protective vaccine TNX-1800 against the new coronavirus disease, COVID-19.

This new research collaboration will develop and test a potential horsepox vaccine that expresses protein from the virus that causes COVID-19 disease in humans.

The coronavirus that causes COVID-19 is called SARS-CoV-2. 

On February 26, 2020, Tonix Pharmaceuticals Holding Corp. and Southern Research said in a press release they intend to develop the live modified horsepox virus TNX-1800 vaccine for percutaneous administration, based on Tonix’s proprietary horsepox vaccine platform.

Under the terms of the research collaboration, Southern Research will test one or more vaccine constructs in the Tonix horsepox vector that express one or more proteins or protein fragments from the virus that causes COVID-19.

The first such potential vaccine is TNX-1800, which is based on synthesized horsepox.

Tonix has previously reported that the horsepox vaccine has efficacy as a vaccine and good tolerability in mice and cynomolgus macaques.

Horsepox is closely related to vaccinia vaccines, which are a group of orthopoxviruses that have been used as smallpox vaccines.

Horsepox and vaccinia are closely related orthopoxviruses that are believed to share a common ancestor.

The name “horsepox” was derived from the animal from which the virus was isolated.  The natural host is presumed to be wild rodents. 

Dr. Seth Lederman, CEO of Tonix Pharmaceuticals said in the press release, “Although vaccinia vectors are available, different orthopoxvirus strains may behave differently as vectors in part because of their different repertoire of genes that modulate immune responses and host range.”

“Potential advantages of horsepox are the strong immunogenicity we observed in macaques and mice with good tolerability.” 

“The protein synthesis connected with a replicating live virus vaccine provides direct antigen presentation, which can stimulate cellular immunity in addition to humoral immunity.”  

Dr. Lederman was formerly an associate professor at Columbia University and made significant original contributions to immunology.

Currently, Tonix is developing the TNX-801 vaccine as a potential smallpox preventing vaccine for the U.S. strategic national stockpile and as a monkeypox preventing vaccine.

Molecular analysis suggests that TNX-801 has relatively “complete” left and right inverted terminal repeats (ITRs) while different vaccinia isolates have a variety of deletions in the left and right ITRs.  

Therefore, TNX-801 has additional genes, relative to vaccinia vaccines, that may play roles in host immune interactions and one or more of such proteins may serve as antigens for protective immunity, says the company.

No new gene elements were added to the natural isolate and the small plaque size in culture appears identical to the U.S. Centers for Disease Control publication of the natural isolate.

Founded in 1941, Southern Research is an independent, 501(c)(3) nonprofit, scientific research organization with more than 400 scientists and engineers working across four divisions. Further information about SR can be found at Southern Research.

Tonix is a clinical-stage biopharmaceutical company focused on discovering and developing small molecules and biologics to treat pain, addiction, and psychiatric conditions. 

SARS-CoV-2 preventive vaccine development news is published by Precision Vaccinations.