Usefulness of Neospora caninum dense granule 1 based-iELISA for the detection of canine neosporosis

抄録

Neospora caninum is an apicomplexan parasite that causes abortion in cattle and sheep. Dog is the main host of N. caninum and infected one shows neurologic disorders. Accurate diagnosis is important particularly under lacking of treatment and vaccination measures. Herein, we targeted the evaluation of diagnostic ability of recombinant protein NcGRA1(rNcGRA1) for detection of specific antibody (IgG) against N. caninum in mice and dogs. The rNcGRA1 was expressed using the E. coli expression system. Diagnostic ability of rNcGRA1 was tested against experimental mouse and dog sera, as well as field dog sera. Simultaneously, same serum samples were tested against rNcSAG1 and Neospora lysate antigen (NLA)-based iELISA. In the N. caninum experimentally infected mice, specific IgG antibodies to NcGRA1 were detectable from 14 days post infection (dpi), and increased at 28 dpi with no detectable antibody levels in the negative control or Toxoplasma gondii infected-mouse sera. In experimentally infected dog sera, the performance of rNcGRA1 was proficient in demonstrating IgG antibody at 28 dpi. In case of field dog sera (N=18), seropositive rate was 44.4% and 22.2% for rNcGRA1 and rNcSAG1-based iELISAs, respectively. These results show that the rNcGRA1 is a novel useful diagnostic antigen for serological detection of N. caninum in dogs.