Immune response to Neospora caninum native antigens formulated with immune stimulating

MOORE DP; VERNA A; ECHAIDE I; LEUNDA MR; CANO A; ZAMORANO PI; PEREYRA S; ODEÓN AC; CAMPERO CM

Monona Terrace Convention Center, Madison, WISCONSIN, USA

Conferencia; The 5th International Veterinary Vaccines and Diagnostics Conference; 2009

The aim of this study was to compare the immune responses to live N. caninum tachyzoites and N. caninum native antigens formulated with immune stimulating complexes (ISCOMs) in calves. Fifteen calves were used in this study: 3 were inoculated intravenously with 1x108 live tachyzoites (Group A), 3 were inoculated with N. caninum native antigens (750ug/dose) formulated with ISCOMs (Group B); 3 were inoculated N. caninum native antigens in phosphate-buffered saline (PBS) (Group C); 3 received ISCOM-MATRIX (ISCOMs without antigen) (Group D) and 3 were mock infected controls receiving PBS (Group E), all these last four groups were inoculated by subcutaneous via. Humoral immune responses were tested by an indirect enzyme-linked immunosorbent assays (ELISAs) for detecting total IgG and its subisotypes and also by Western blot. IFN-g production in plasma was quantified using a commercial kit (Bovigam). In week 2 after inoculation, there were Neosporaspecific antibodies developed in animals from Groups A and B. OD values were higher in Group B compared with Group A from week 6 to 11 (P<0.05). Experimentally infected calves revealed a predominant IgG2 response; however, a predominant IgG1 response was observed in animals from Group B. Although the pattern of bands observed by Western blot differed in the time of showing, immunodominant antigens of 60-62, 37, 34 and 17 kDa were observed when testing sera from calves in Groups A and B. Levels of IFN-g were similar for Groups A and B (P>0.05). Humoral immune response and IFN-g production induced by N. caninum native antigens formulated with ISCOMs were similar to those found in calves inoculated with live parasites.