This vaccine uses a bacterial vector to deliver multiple Brucella melitensis antigens that should produce enhanced immunogenicity and prevent brucellosis in farm animals. Brucella abortus, melitensis and suis infect cattle (and other large ruminants), sheep and goats, and swine, respectively. Infections are most prevalent in farm animals in the developing world and also in wildlife populations in the developed world. Brucellosis causes abortion and sterility in mammals resulting in substantial economic losses in the livestock industry and is a significant human health problem, especially in the developing world due to consumption of unpasteurized milk and milk products leading to Brucella transmission to humans. Current live attenuated vaccines still cause some disease, are not very effective in preventing abortion, and are unsafe in humans.
Researchers at the University of Florida are developing a highly immunogenic vaccine for brucellosis that should prevent B. melitensis infection but also be safe because it uses specific bacterial proteins rather than the attenuated, or killed bacteria. Additionally, this vaccine can be orally-administered, which will make it easier to use, especially in developing countries.
Orally administered brucellosis vaccine for livestock that prevents B. melitensis infection and induces effective immunity, but is safer than currently available vaccines
Dr. Curtiss’ lab is developing a protective immunity enhanced Salmonella vaccine against Brucella melitensis that overcomes the limitations of current vaccines. The researchers have eliminated Salmonella’s means to suppress and evade induction of acquired immunity while increasing its ability to recruit and stimulate innate immunity to collectively enhance induction of protective immunity. The vaccine vectors display in vivo regulated delayed expression of attenuation and regulated delayed in vivo synthesis of protective antigens. Both attributes enable vaccine vectors at the time of mucosal administration to invade and effectively colonize lymphoid tissues as efficiently as the wild-type parental Salmonella to maximize immune responses to antigens delivered by vaccine vector. Lastly, the vaccine vectors display regulated delayed lysis in vivo to release a bolus of protective antigens. This attribute is a definitive means of attenuation and provides biological containment with no vaccine persistence in vivo or survival if excreted. Scientists have made regulated lysis plasmids encoding 10 different B. melitensis antigens as well as two constructs with fusions of three antigens each. These B. melitensis antigens are more than 95 percent identical in amino acid sequences to the homologous antigens in B. abortus. These vector constructs have been tested in mice.
