Researchers from the University of Illinois at Chicago have found that zinc-oxide nanoparticles, called ZOTEN, have negatively charged surfaces that can attract herpes simplex virus-2 (HSV-2) and prevent it from entering cells, which could help build natural immunity against the virus.
The results of their study were published in the Journal of Immunology.
“We call the virus-trapping nanoparticle a microbivac, because it possesses both microbicidal and vaccine-like properties,” said co-author Deepak Shukla, PhD, professor of ophthalmology and microbiology and immunology at the University of Illinois at Chicago College of Medicine, in a prepared statement. “It is a totally novel approach to developing a vaccine against herpes, and it could potentially work for HIV and other viruses.”
Approximately 15% of people between 14 and 49 years of age carry HSV-2, according to the Centers for Disease Control and Prevention (CDC). Dr Shukla explained that the ZOTEN nanoparticles could be used as an active ingredient in a topically-applied vaginal cream that would provide immediate protection against HSV-2 and help build immunity for long-term protection.
“Your chances of getting HIV are 3 to 4 times higher if you already have genital herpes, which is a very strong motivation for developing new ways of preventing herpes infection,” Dr Shukla added.
The negatively charged surfaces of ZOTEN attract the HSV-2 virus through its positively charged proteins along the outer envelope. Once HSV-2 is bound to the nanoparticles, the virus cannot infect cells, although the bound virus is susceptible to processing by dendritic cells in the vaginal lining. The dendritic cells then produce antibodies that identify infected cells and kill them before the virus can spread.
The ZOTEN particles were synthesized by technology developed at Kiel University in Germany, and protected with a joint patent with the University of Illinois at Chicago.
Researchers swabbed female mice with HSV-2 and an ointment containing ZOTEN, and found that they had significantly fewer genital lesions and less inflammation of the central nervous system than mice treated with ointment without ZOTEN. They used a high-resolution fluorescence microscopy to watch the immune cells attack the virus on the nanoparticles.
“It’s very clear that ZOTEN facilitates the development of immunity by holding the virus and letting the dendritic cells get to it,” Dr Shukla noted.
He added that if ZOTEN particles are safe and effective in humans, a cream containing ZOTEN could be applied vaginally just prior to intercourse. Additionally, if a woman used it regularly, she could potentially develop immunity against the virus.
- Antoine TE, Hadigal SR, Yakoub AM, et al. Intravaginal Zinc Oxide Tetrapod Nanoparticles as Novel Immunoprotective Agents against Genital Herpes. J Immunol. 2016. doi:10.4049/jimmunol.1502373.
- Parmet S. Nanoparticles hold promise as double-edged sword against genital herpes. UIC News Center website. https://news.uic.edu/nanoparticles-hold-promise-as-double-edged-sword-against-genital-herpes. April 27, 2016. Accessed May 11, 2016.