BACKGROUND:  Tularemia infections, which are caused by Francisella tularensis, can range from mild illnesses to acute sepsis. Health experts suspect that tularemia is underrecognized and underreported; thus, the incidence of tularemia infections could be higher than the 200 cases reported each year in the United States. While natural infections of F. tularensis have become less of a threat, recent history indicates that the bacterium could be used as a biological weapon. In the 1950s and 1960s, several countries-including United States and Soviet Union-experimented with weaponizing F. tularensis in an aerosolized form. Tularemia infections caused by aerosol release could cause a variety of clinical consequences, the most likely of which being primary pneumonic tularemia, a highly fatal disease. The risk of casualties is of grave concern if the scale of exposure is greater than the capacity of the medical care system. Given the lack of approved vaccines against tularemia, a method to prevent F. tularensis infections will be needed to protect against use of this agent as a bioweapon.

INNOVATION:  The present invention describes novel vaccines that utilize a live attenuated recombinant vector to deliver F. tularensis immunogenic antigens in host cells in a way that mimics F. tularensis. Like F. tularensis, the vector is phagocytized by host mononuclear phagocytes, escapes from the phagosome, and inhabits the cytoplasm of the host cell. Subsequently, the vector releases immunoprotective antigens into the host cell cytoplasm for processing and presentation to the immune system in a way that mimics the processing and presentation of the same antigens by F. tularensis. Consequently, the vaccines described in the subject invention stimulate a highly potent immunoprotective response against F. tularensis challenge in the mammalian host.

POTENTIAL APPLICATIONS:  The invention can facilitate the development of tools, such as diagnostics, therapies, and vaccines, to defend against possible bioterrorism-related disease outbreaks.

ADVANTAGES

• Safer and more efficacious than previously developed tularemia vaccines.
• Better characterized and more stable in comparison with existing vaccines.

DEVELOPMENT-TO-DATE:  Tested in animals.

Reference: UCLA Case No. 2007-223