Infection with Babesia bovis induces the appearance of antibodies against phosphatidylcholine with high selectivity

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

Mendoza,

Otro; VII Congreso de la Sociedad Argentina de Protozoología.; 2005

We previously have shown that the apicomplexan intraerythrocytic parasite Babesia bovis, has an intense rate of phosphatidylcholine (PC) biosynthesis (Florin-Christensen J et al, MBP 106 (2000) 147-156). By contrast, this phospholipid is absent or almost absent in the host erythrocytes, which expose sphingomyelin (SM) instead. 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 used an ELISA assay to detect IgM with an anti bovine IgM–HRP conjugate. We compared the immune responses against the two choline phospholipids, PC and SM, observing a consistently strong response against PC but not against SM. Since they share the choline polar head group, this appears not to be the determinant epitope in the anti phospholipid response. The antibodies to PC generally peak three weeks after infection in both strains. It should be noted that at this time, antibodies against other immunodominant self surface antigens appear after infection of the bovines. Our results suggest that PC may be an important component of a possible immunoprofilactic strategy against Babesial infections, since it would target the parasite PC without affecting the erythrocyte SM counterpart, thus exploiting the special composition of bovine erythrocytes and their immune implications. This work was supported by FONCYT and CONICET.