Immunoblot showing SMORF expression in Babesia bovis T2Bo and Mo7.2 strains. (A) Electroeluted recombinant SMORF (rSMORF), control recombinant patatin from Anaplasma marginale (rPatatin), and control non-recombinant Escherichia coli extract (Ctrl E. coli) were electrophoresed and immunoblotted with anti-SMORF peptide serum. (B) Antigen preparations (from B. bovis strain, parasites and control) as indicated along the top of the panel were electrophoresed and immunoblotted with anti-SMORF peptide or pre-immune rabbit serum as indicated below the panel. nRBC refers to an antigen preparation of uninfected bovine erythrocytes. The panel immunoblotted with monoclonal antibody raised against B. bovis merozoite surface antigen-1 (MSA-1 Mab) shows that the T2Bo and Mo7.2 lanes are loaded with equal amounts of parasite protein. The lane marked with an asterisk is an overexposure of the Mo7.2 lane immunoblotted with SMORF peptide antiserum, and the arrow points to the prominent 18 kDa polypeptide. Multiple bands are present in T2Bo, but in Mo7.2 are only seen when the immunoblot is overexposed.