immunological and molecular evaluation of a new variety of neospora caninum in balb/c mice

Neospora caninum is a protozoan parasite which cause storm abortion in cattle and leads to economic damage in production industry. there is no effective commercial vaccine against this infection. the aim of the present study was to evaluate the immune potential of an attenuated live strain in pregnant and non-pregnant mice. in this study, 30 balb/c mice were randomly divided in to 3 groups: 1) subcutaneously injected with cultue media. 2): mice received unattenuated strain of n.caninum (5´106). 3) mice inoculated with attenuated strain of n.caninum tachyzoite (5´106). similarly, in pregnant mice, all mice were injected with vaccine on day 5-7 of pregnancy and one group just received challenge dose. all groups were observed for 2 weekes, then challenged with virulance strain. blood samples were collected and pcr and histopathology test were performed on tissue samples. results of non-pregnant mice showed a significant difference in humoral and cellular responses between virulance and attenuated strian to the control group (p≤0.05). in addition, the least tissue damaged was observed in attenuated live group. in pregnant mice, the maximum successful delivery was obtained in mice had injected with attenuated strain. moreover, dna of parasite found in the tissues of pups from attenuated strain was 20% which had a significant difference with control group (p≤0.05), and the mortality rate of this group was less than other groups. the attenuated strain could protect from tissue damage and there was a considerable difference between attenuated strain and other groups (p≤0.05). in accordance to the ability of attenuated live strain in prevention from cerebral damage and production of vertical transmission, we conclude the attenuated strain could be used as a suitable candidate for vaccine evaluation against neosporosis in future studies.