Herpes simplex virus 2 (HSV-2) results in genital herpes, impacting over 500 million individuals globally. The virus penetrates through the vaginal lining and rapidly targets the nervous system, residing in nerve clusters adjacent to the spine, which renders it resistant to elimination by medications. The development of a vaccine has proven difficult, partly because conventional vaccines focus on the bloodstream and lymph nodes, thereby neglecting the mucosal entry points.
Akiko Iwasaki and her team at Yale have been pioneering a “prime and pull” technique. This method consists of systemic priming followed by recruiting immune cells to the vaginal lining utilizing chemokines and DNA that stimulates the immune system. Nevertheless, these methods were either somewhat effective or led to inflammation.
The group led by postdoc Sachin Bhagchandani designed the BEACON nanoparticle. It merges negatively charged immune-stimulating CpG DNA with positively charged chemokine CXCL9, creating stable spheres that can successfully target antigen-presenting cells without inducing significant inflammation.
The vaccination regimen entails an intramuscular mRNA injection, succeeded by the administration of a protein and BEACON into the vaginal tissue. Tests in mice indicated positive results, featuring strong local immune reactions and considerable decreases in virus levels.
Although encouraging, hurdles persist: the necessity for both T and B cell responses, variances between mouse and human biology, and the fact that the method is presently preventive rather than therapeutic. The team is endeavoring to formulate a version suitable for human use, possibly expanding the method to other sexually transmitted infections such as HIV and chlamydia. The aim is ultimately to develop a vaccine that lessens both the physical and social burdens of herpes.
DOI / Source: [10.1126/sciimmunol.aea6419](https://doi.org/10.1126/sciimmunol.aea6419), *Science Immunology*
**FAQ**:
**Why can’t a typical injected vaccine prevent genital herpes?**
Standard vaccines do not concentrate on the vaginal mucosa, enabling HSV-2 to access the nervous system prior to the intervention of circulating immune cells.
**What is the mechanism behind the BEACON nanoparticle?**
BEACON integrates CpG DNA and CXCL9, drawing and activating immune cells specifically at the site of viral entry, thus reducing inflammation.
**Is there potential for this to be effective for men?**
Absolutely. Research is investigating a nasal delivery system to apply this method to men.
**Is this nearing availability for public use?**
Not at this moment. Current results are derived from mouse studies, but human trials are a goal for the future after further advancements.