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The new vaccine confers a high level of safety because it containsinactivated vaccinia virus, not the live virus contained in current smallpoxvaccines, according to the scientists. Live viruses can elicit adversereactions; yet previous attempts to use inactivated virus have failed to rousean adequate immune response against smallpox, the scientists said.
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The current study in mice demonstrates that NanoBio's killed-virus vaccineelicits a robust immune response because it delivers immune-alerting antigensdirectly to the lining of the nasal mucosa, where the virus first enters thebody. Immune cells inside the nose immediately recognize the foreign invaderand quickly build an immune response against it, a process known as "mucosal"immunity.
Mucosal immunity provides a critical first response against respiratoryviruses, yet injected vaccines do not induce mucosal immunity, said James R.Baker Jr., M.D. founder and chairman of NanoBio Corporation. NanoBio is aspin-off from the University of Michigan.
"The key finding is that we have validated in animals a new means ofimmunization that produces a unique and highly effective immune responsewithout the potential risks of smallpox vaccination that are no longerconsidered acceptable in the population at large," said Baker.
"The safety and speed of our nasally delivered vaccine would provide thenecessary protection to the public in the event of a bioterrorist attack or anatural outbreak of a related orthopoxvirus infection such as monkeypox," hesaid.
Results of the study are published in the February 2008 issue of Clinicaland Vaccine Immunology. The study is the first to demonstrate protectiveimmunity against smallpox using a vaccine with inactivated virus, said Baker.
The data are the latest in a series of preclinical vaccine studies thatvalidate NanoBio's patented nanoemulsion platform, a suspension of oil, water,alcohol and antimicrobial surfactant together with antigens from specificpathogens. The nasally delivered vaccines easily penetrate mucous membranes,where dendritic cells engulf the antigen and immediately present it to theimmune system.
This rapid awakening of the immune system via mucous membranes negates theneed for inflammatory stimulants used in traditional injected vaccines, whichcan cause pain and swelling at the site of vaccination, said Baker.
Animal studies indicate that NanoBio's vaccines quickly trigger robustimmunity -- without adverse effects -- against a wide array of viruses andbacteria, including influenza, hepatitis B, RSV, anthrax and HIV.
A study to be published this month in the journal AIDS Research and HumanRetroviruses demonstrates that their HIV vaccine produces both mucosalimmunity as well as systemic immunity -- the immune system's long-term memorythat enables it to recognize and combat future infections.
Both types of immunity are critically important, but developing mucosalimmunity is particularly valuable in combating sexually transmitted diseasesbecause they enter the body through mucous membranes, added Baker. Vaccinesthat are delivered to one mucosal surface, such as inside the nose, buildimmunity at distant mucosal surfaces as well.
"When you present an infection on one mucosal surface, the immune cellsthat are recruited at that surface also traffic throughout all the mucosalsurfaces," Baker said. "Our HIV study suggests that the nanoemulsion should beevaluated as a mucosal adjuvant for multivalent HIV vaccines."
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