|Urban, Jr., Joseph|
Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2004
Publication Date: 8/1/2004
Citation: Kringel, H., Dubey, J.P., Beshah, E., Hecker, R., Urban, Jr., J.F. 2004. CpG- oligodeoxynucleotides enhance porcine immunity to Toxoplasma gondii. Veterinary Parasitology. 123:55-66. Interpretive Summary: Infectious agents in the food chain can compromise food safety. Some of these disease interactions are rather intractable because of the close association between infectious agents and their host. Pigs can become infected with Toxoplasma gondii that is spread by domestic cats and can infect the edible tissue of the pig. Control of this infection is difficult because it can accompany the feed that pigs eat. People who hav deficient immune systems can become infected with this organism if they ingest infected pork. This event is rare, but is problematic for people on immunotherapy, with age-related disorders or who have acquired immune deficiency. Vaccination of pigs against the infection would be a useful form of control, but no effective and safe vaccine exists. The current report shows that pigs can be protected when given a live-attenuated form of the infection along with an immune stimulator called CpG. This is the first report in swine of such enhanced protection and provides a basis for the development of molecular vaccines that could be used to control the infection in pigs and reduce the threat of infection in the food supply.
Technical Abstract: Protection against a challenge infection with Toxoplasma gondii VEG strain oocysts was examined in pigs after vaccination with T. gondii RH strain tachyzoites with or without porcine specific synthetic oligodeoxynucleotides (ODN) containing immunostimulatory CpG motifs. Six groups of pigs were immunized with Incomplete Freund s Adjuvant and either vehicle, tachyzoites alone or in combination with three different doses of CpG ODN or with CpG ODN alone. Protection from challenge was significantly (P<0.05) improved in pigs vaccinated using CpG ODN as an adjuvant with tachyzoites compared to all other groups. The CpG ODN tachyzoite-immunized pigs also had higher parasite specific IgG antibody, higher IFN-g, reduced IL-4 gene-expression, no clinical signs of disease and 52% had no demonstrable tissue cysts after the challenge infection. These data indicate that CpG ODN is a potential safe and effective adjuvant for the T. .gondii RH strain vaccine in pigs.