CAMBRIDGE, Mass., Jan. 11, 2021 /PRNewswire/ -- A study of Rational Vaccines' herpes simplex virus candidate published in the Journal of Virology demonstrates that the vaccine candidate, RVX10, offered robust protection against ocular herpes simplex virus 1 (HSV-1) infection in vaccinated mice.
The major finding of the study, "Herpes Simplex Virus 1 (HSV-1) 0ΔNLS Live-Attenuated Vaccine Protects against Ocular HSV-1 Infection in the Absence of Neutralizing Antibody in HSV-1 gB T Cell Receptor-Specific Transgenic Mice," found that the company's RVX101 vaccine candidate used to immunize a unique mouse line (does not generate much of a neutralizing antibody response to the virus) was shown to provide highly protective immunity and prevent herpes-associated neovascularization. This robust efficacy was found to be correlated with CD8+ T cells, since depleting these cells after vaccination, but before challenge with HSV-1 eliminated any efficacy realized by the vaccine.
Ocular HSV can cause disease in any layer of the eye and is mainly spread by direct contact. A variety of eye diseases are associated with ocular HSV infection, including conjunctivitis, iridocyclitis, acute retinal necrosis and keratitis.
HSV-1 is typically associated with ocular herpetic disease, although herpes simplex virus 2 (HSV-2) has been shown to have some implications, as well.
An estimated 500,000 people in the U.S.A have HSV ocular disease, with 50,000 new cases of severe visual impairment or blindness diagnosed each year. HSV keratitis is also considered an important cause of infectious blindness across the globe.
The paper authors – Gmyrek, G.B., A. Filiberti, M. Montgomery, D.J. Royer, and D.J.J. Carr – also offer up a caveat to the study's findings: While protective, vaccinated mice still showed corneal opacity suggesting their visual axis was impacted by the virus challenge.
"We interpret these results to suggest neutralizing antibody is likely necessary to preserve the visual axis following vaccination in the experimental mouse model," said Dr. Daniel J.J. Carr, one of the paper's authors who holds the Stanton L. Young Chair in Ophthalmology in the Department of Ophthalmology, University of Oklahoma Health Sciences Center. Dr. Carr is also a member of Rational Vaccines' scientific advisory board.
A summary of the study's major findings is:
In the absence of neutralizing antibody, the vaccine still protects mice from virus-mediated death, reducing virus in the nervous system, and preventing corneal neovascularization.
In the absence of neutralizing antibody, some aspects of tissue pathology (e.g., corneal opacity) in the cornea are evident in vaccinated animals.
"Ocular herpes is considered the most common cause of infectious corneal blindness in the U.S., and 1.5 million people around the world suffer with HSV keratitis," said Rational Vaccines CEO Agustin Fernandez. "This study is another indication that we are committed to applying the best of science and standards to validate our vaccine platform with data-driven results, closely following all regulatory guidelines as we work assiduously against herpes and related diseases."
About Rational Vaccines
Rational Vaccines develops rationally engineered, live attenuated viral immunotherapeutic and prophylactic vaccine candidates, particularly focused on combating all diseases resulting from herpes simplex virus 1 (HSV-1) and herpes simplex virus 2 (HSV-2) infections. Led by our team of world-renowned scientists and closely following all regulatory guidelines, the company currently has seven vaccine candidates in the pipeline. We are confident our team and technology will revolutionize the treatment, prevention, and diagnosis of herpes and herpes-related diseases so we can bring hope and healing to a world suffering from these recurring infections. Based in Cambridge, MA, Rational Vx is also joining the battle against COVID-19 with a serological assay currently in development, and a future COVID-19 vaccine planned. For more information go to https://rationalvaccines.com or email [email protected].