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We are developing vaccines to protect the public from life-threatening diseases. Our proprietary vaccines are based on parainfluenza virus 5 (PIV5), also known as canine parainfluenza virus. We insert a gene encoding an antigen of interest into the PIV5 genome.

When one of our vaccine vectors is introduced to a host, it undergoes several rounds of self-limited replication, inducing robust immune responses with as few as one dose.

In preclinical studies, we have shown that our vaccines robustly produce three forms of immunity:

1. Cellular immunity: Cellular immunity is essential for fighting off viral infections. While antibodies can slow down a virus, some cells will still become infected, so cellular immunity is needed to eliminate those cells. Our vaccines regularly generate robust cytotoxic T-cell responses, a critical component of cellular immunity.

2. Humoral immunity: A key defense against future infections, humoral immunity produces antibodies in the blood. The efficacy of vaccines is most easily evaluated by the humoral antibody response they generate, and our PIV5-based vaccines produce a strong antibody response with a single dose.

3. Mucosal immunity: Comprised of secretory antibodies at the mucosal surface, mucosal immunity is the first line of defense against infection, blocking pathogens at their site of entry into a host (e.g. the mucosal lining of the respiratory tract). Our intranasal vaccines generate mucosal immunity because they are introduced through the nasal mucosa; injected vaccines do not.

PIV5 is a respiratory virus, so our vaccines are "born intranasal". Delivered as a spray in the nose, without injections, our vaccines will facilitate broad delivery not only to pediatric and other needle-hesitant populations, but also in parts of the world where healthcare professionals are scarce.

For over 50 years, PIV5 itself has been used as part of a canine distemper (kennel cough) vaccine. Dogs dosed (intranasally) with the vaccine will often sneeze, exposing veterinarians to PIV5, and they will continue to shed virus for a few days, often exposing dog owners to PIV5. Many people already have antibodies against PIV5, proof that they have been exposed to the virus.¹ Yet despite decades of such exposure, PIV5 has never been known to cause disease in humans.

Because PIV5 replicates in self-limited fashion, a relatively small number of viral particles (compared with other viral vectored vaccines) is needed to make each vaccine dose. With a relatively small bioreactor, we can theoretically produce millions of doses per month of our vaccines. Conventional virally-vectored vaccines need manufacturing capacity measured in 10,000s of liters to produce a similar number of doses. This makes our PIV5 technology ideal for rapidly responding to emerging infectious threats, as well as for defending against existing ones worldwide.

¹ Chen et al (2012), Evaluating a parainfluenza virus 5-based vaccine in a host with pre-existing immunity against parainfluenza virus 5, PLOS One, 7:e50144. Like humans, dogs generate neutralizing antibodies against PIV5 from prior exposure, yet these do not interfere with the activity of a PIV5-based vaccine.