This family represents the immunodominant surface antigen of Theileria parasites including equi merozoite antigen-1 (EMA-1) and equi merozoite antigen-2 (EMA-2) [1]. The protein shows variation at a putative glycosylation site, a potential mechanism for host immune response evasion [2].

1: Genetic and biochemical analysis of erythrocyte-stage surface antigens belonging to a family of highly conserved proteins of Babesia equi and Theileria species. Knowles DP, Kappmeyer LS, Perryman LE; Mol Biochem Parasitol 1997;90:69-79. PMID:9497033

2: Selection of diversity at putative glycosylation sites in the immunodominant merozoite/piroplasm surface antigen of Theileria parasites. Shiels BR, d'Oliveira C, McKellar S, Ben-Miled L, Kawazu S, Hide G; Mol Biochem Parasitol 1995;72:149-162. PMID:8538686