An Opisthorchis viverrini homologue of Sm -TSP-2, a vaccine antigen expressed in the tegument of Schistosoma mansoni. Multiple sequence alignment comparing the ORF of OvAE953 with Sm-TSP-2 from S. mansoni (GenBank AF521091) and human CD63 (NM_001780). Both Sm-TSP-2 and CD63 sequences shown here are truncated at the C-terminus (fourth transmembrane domain and C-terminal tail are not shown) for comparative purposes because OvAE953 is a partial sequence. Black boxes denote identical residues shared by two or more of the sequences. Grey boxes denote conservative substitutions. Dashed lines denote the predicted transmembrane (TM) domains of Sm-TSP-2; the solid line represents the extracellular (EC) loop 2 region of Sm-TSP-2 .