A novel ELISA assay to investigate antiphospholipid antibodies in the infection of bovines with Babesia bovis.

GIMENEZ G;; SUAREZ, CE;; ECHAIDE, I;; ZAMORANO, P;; ISOLA, ELD;; FLORIN-CHRISTENSEN, M;; FLORIN-CHRISTENSEN J.

Montevideo, Uruguay

Simposio; 12th International Symposium of the World Association of Veterinary Laboratory Diagnosticians (WAVLD).; 2005

We previously have shown that the apicomplexan intraerythrocytic parasite Babesia bovis, has a high rate of phosphatidylcholine (PC) biosynthesis (Florin-Christensen, J. et al, MBP 106 (2000) 147-156). This phospholipid is absent or almost absent in the host erythrocytes. Infection with B. bovis, could lead to exposure of PC to antigen presenting cells and could thereby generate an immune response. In this study we investigated the humoral response to experimental infection with either a highly pathogenic strain (S2P) or an attenuated (R1A) one, from day 0 to 66. We employed an ELISA assay devised ad hoc. We used NUNC Maxisorp polystyrene microtitre plates, a commercial blocking agent from Roche, anti bovine IgM–HRP conjugates from KPL and OPD from DAKO as the developing reagent. Sera were tested in a fixed dilution of 1:100 in blocking buffer solution. Results were expressed comparing the OD 490 nm measured at the different times with respect to the pre-immune sera. We found a conspicuous raise in anti PC - IgM antibodies. The response to PC generally peaks three weeks after infection in both strains. It is noteworthy that at this time, antibodies against other immunodominant antigens appear in the infected bovines. In other words, the immune response against PC is simultaneous with the general humoral response against B. bovis antigens, which are lipid anchored proteins. This suggests a possible participation of the same antigen presenting cells in the responses to these antigens. Furthermore, PC may be a significant component in a vaccinal preparation to fight Babesiosis in bovines.