HSP81.2 from Arabidopsis thaliana enhances the immune response against NcSAG1 from Neospora caninum protein and partially protects mice from congenital neosporosis

BENGOA LUONI, S.; CORIGLIANO, M.; CLEMENTE, M.; SANDER, V.

Madrid

Encuentro; 4th International Meeting on Apicomplexa in Farm Animals; 2017

Neosporosis is caused by Neospora caninum, the main pathogen agent responsible for economic losses in the cattle industry. Currently, there are not cost-effective control options for neosporosis, and the development of a vaccine appears to be the best approach. In this study we administrated a novel vaccine formulation including the well characterized major surface antigen of N. caninum (NcSAG1) and as adjuvant the 81 KDa heat shock protein (HSP81.2) from Arabidopsis thaliana in a murine model of congenital neosporosis. Both proteins were expressed in Escherichia coli. BALB/c female mice were i.p. immunized on 0 and 15 dpi with a combination of equimolar quantities of rNcSAG1(10 µg) and rAtHSP81.2(30 µg) or each protein alone. Control group was administered 200µl of PBS. Mice were bled on 0, 15, 30, 60 and 90 dpi to determine total Immunoglobulin G (IgGt), IgG1 and IgG2a. On 60 dpi, mice were mated. Five pregnant mice per group were s.c. challenged with 2.106 NC-1 N. caninum tachyzoites on day 7.5-10.5 after vaginal plug was observed. Five pregnant mice from the control group were not challenged. The offspring were euthanized 60d of age. High IgGt, IgG1 and IgG2a specific antibody levels directed against rNcSAG1 protein were developed by the group that received the combined vaccine formulation and their offspring showed improved survival rates. In conclusion, the rNcSAG1+rAtHSP81.2 vaccine was able to induce an important humoral response in immunized mice and confers partial protection against N. caninum to their offspring encouraging us to further study its effectiveness against congenital neosporosis.