Histopathological lesions in placenta and fetuses from heifers vaccinated with experimental vaccines and challenged with Neospora caninum

HECKER YP; CÓCERES V; MORRELL E.; LISCHINSKY L.; CANO D; MANES J; HOZBOR F; VENTURINI MC; CAMPERO CM; MOORE DP

Lisboa

Congreso; Apicomplexa in farm animals- International meeting; 2012

Escola Superior de tecnologia da Saude de Lisboa

The aim of this study was to characterize the histophatological lesions in fetuses from heifers vaccinated with native antigens and recombinant proteins from Neospora caninum formulated with immune stimulating complexes (ISCOMs). Twenty seronegative N. caninum pregnant heifers were involved: 4 were inoculated intravenously with 1x108 live tachyzoites of Nc 6 strain (Argentine isolation) (Group A); 4 were inoculated with native antigens obtained from tachyzoites of Nc 6 strain (750ug/dose) formulated with ISCOMs (Group B); 4 were inoculated with a mix of four recombinant proteins (SAG1, PIs, Hsp20, GRA7 (30ug of each protein/dose)) also formulated with ISCOMs (Group C); 4 received ISCOM-MATRIX (Group D) and 4 were controls receiving PBS (Group E). All the heifers of these last four groups were inoculated twice by subcutaneous via with interval of 21 days previous mating. After pregnancy was confirmed, all animals were challenged at day 70 of gestation with 4x107 tachyzoites of Nc 1 strain. Multiple sections of central nervous system, heart, lung, liver and placenta were examined by routine histological methods. N. caninum characteristic lesions were evaluated according to their severity as follow: no lesion (=0), mild (=1), moderate (=2) and severe (=3) lesions. The information recorded from each experimental group were statistically analyzed observing a lower score lesion only in specimens from Group A (p<0.05). Either fetuses or placentas from groups receiving the experimental vaccines formulated with native antigens or recombinant proteins of N. caninum did not differ from those observed in specimens from Groups D and E.