Immunodominant antigens of Neospora caninum in experimentally infected water buffaloes (Bubalus bubalis)

CAMPERO L.M.; KONRAD J.L.; MOORE D.P.; BACIGALUPE D.; RAMBEAUD M.; CAMPERO C.M.; VENTURINI M.C.

Lisboa

Congreso; Apicomplexa in Farm Animals. International Meeting. Lisbon. 25-28 October, 2012; 2012

Neospora caninum is an Apicomplexan parasite related to abortion in beef and dairy cattle. Water buffaloes (Bubalus bubalis) are intermediate hosts for N. caninum. Around 80,000 heads of water buffaloes are raised under extensive conditions in wet areas of the northeast of Argentina and a seroprevalence for N. caninum of 64% has been reported. There is little information available for the diagnosis of neosporosis in wild species like water buffaloes , for that reason it is important to count with proper serological tests. The aim of this study was to identify antigens for immunodiagnosis of N. caninum based on the serological response from experimentally infected (EI) water buffaloes and to compare the immunoblotting pattern with EI cows. Two Mediterranean water buffaloes seronegative to N. caninum were inoculated intravenously with 108 tachyzoites of N. caninum Nc-1 strain. Blood samples were taken at days 0, 7, 14, 21, 28 postinoculation. Sera from EI cows intravenously inoculated with 108 tachyzoites of Nc-1 strain were also used. Indirect Fluorescence Antibody Test (IFAT) and Immunoblot (IB) with non-reduced antigen from Nc-1 and sera dilution of 1:100 were performed to all serum samples. Sera were classified as positive when IFAT titre more than 1:50 and 2 or more immunodominant antigens (IDA) were recognised. The main IDA detected in water buffaloes and cows were: 17, 29, 30, 33, 37 kDa proteins. There was no significant differences in the immunoblotting pattern of recognition in both species except for the presence of a ~26 kDa antigen detected only by cow sera with IFAT titres more than 1:3200 but not in water buffaloes with similar titres. Therefore, these 5 IDA can be used for immunodiagnosis of neosporosis in different species, as it has been probed to be recognised by sera from water buffaloes and cows under the same experimental conditions.