Taking advantage of the polymorphism of the MSA-2 family for Babesia bovis strain characterization.

The Merozoite Surface Antigen-2 (MSA-2) family of Babesia bovis is a group of variable genes which share conserved 5' and 3' conserved ends. These genes encode membrane anchored glycoproteins, named MSA-2a1, a2, b and c, which are immunodominant antigens located on the surface of sporozoites and merozoites. In this work, we have analyzed the sequences of the msa-2a1, a2 and 2b genes in two geographically distant strains from Mexico and Argentina and detected a certain degree of genotypic diversity that can be exploited for the development of a new molecular tool for the discrimination of B. bovis field samples. Here, we describe a PCR restriction assay based on the msa2-a1, -a2 and -2b genes of B. bovis. When field strains from Argentina, Mexico and USA were analyzed, the results showed a strain-specific band pattern indicating the presence of differentially located BspMI restriction sites. This approach provides a simple method for the genotyping/strain differentiation of B. bovis field samples.