Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/1994
Publication Date: N/A
Interpretive Summary: Anaplasmosis and babesiosis are two tick-transmitted blood parasites affecting cattle throughout much of the world. Live, attenuated vaccines and killed whole organism vaccines have provided protection against these diseases. However, due to serious safety and efficacy issues, research has been directed to determining what molecule(s) of the pathogenic organism is responsible for the induction of a protective immune response. This portion of the organism, so called subunit, forms the basis for improved vaccines, and theoretically directs the immune response toward the critical target molecule of the pathogen only, thus solving many of the existing problems. The ultimate goal is to develop synthetic or genetic engineered replicas of the important target molecule. This is no trivial matter, requiring several years to completely develop. In the mean time, conventional subunit vaccines for these two diseases have been shown to be effective, and can serve as improved vaccines in the interim. This report reviews the progress made in such conventional vaccines, and in addition, provides some new data concerning molecules of Babesia that are shed into the culture media used to maintain the parasites in the laboratory. These molecules have been characterized, and used as a vaccine with some degree of protection. While this type of vaccine is not ideal, it appears to offer some improvements over the live attenuated vaccines, and thus has an important role to play in the control of this disease.
Technical Abstract: Tick-borne hemoparasitic diseases of cattle continue to impact the beef industry throughout a large portion of the world. A substantial amount of research is currently focused on development of improved vaccines. The two main approaches being followed are: (1) use of conventional inactivated or native protein subunit vaccines, and (2) development of recombinant DNA technology for expression of selected immunogens. Recombinant or synthetic peptide based vaccines hold promise owing to the exquisitely defined nature of the product. However, the development is long-term, and will require extensive testing and risk assessment before field trials can be considered. Until then, more conventional subunit immunogens may offer an attractive alternative, and can be defined immunologically better than before. This paper reviews progress in the development of improved vaccines for anaplasmosis and babesiosis with an emphasis on the characterization of culture-derived babesial exoantigens. Both in vitro and in vivo information is presented.