Characterization of the immune cell infiltration of cattle and buffalo placentas following experimental inoculation with Neospora caninum during early pregnancy

CANTÓN G; MALEY S; KATZER F; BARTLEY P; KONRAD JL; CASPE SG; MOORE DP; CAMPERO CM; INNES E; CHIANINI F

Lisboa

Congreso; Aplicomplexa in Farms Animals, International meeting, Lisbon, Portugal, 25-28 October 2012.; 2012

Despite Neospora caninum (NC) being a major cause of bovine abortion worldwide, its pathogenesis is not completely understood. NC stimulates host cell-mediated immune responses, and if exacerbated may be responsible for placental damage leading to abortion. Susceptibility of water buffalo (Bubalus bubalis) to NC is not fully understood, although vertical transmission and foetal death has been confirmed after infections. The aim of our studies was to characterise and compare placental immune responses following experimental infection in both species at 70 days of gestation. Cows and water buffaloes were infected with NC at day 70 of pregnancy and culled at 28 days post inoculation. Placentomes were examined by immunohistochemistry using antibodies raised against T-cells (CD3, CD4, CD8, γδTCR), NK and B cells. Foetal death was confirmed in 3 out of 4 infected cows; meanwhile, 1 out of 3 inoculated buffalo carried a death foetus. Placental inflammation in NC-infected cows was generally moderate to severe, being significantly more important in the aborted animals. The inflammation in the buffalo placentas was scarce to severe, and similarly to the bovine placentas, more severe in the placenta carrying the dead foetus. In both species, cellular infiltrates were mainly characterised by the presence of CD3+, CD4+ and γδ T-cells; whereas CD8+ and NK cells were less numerous. The distribution of the different cellular subsets observed in cattle and buffalo placentas was similar. In both species the infiltrates were more severe in the dams carrying dead foetuses. In general, cellular immune infiltrates in the placentomes were less severe in buffaloes, which may explain the lower number of abortion observed in this specie after infection during early gestation.