The sequence of CsGRN encoding 238 amino acids was predicted with molecular weight 25.8 kDa, theoretical point isoelectric (PI) of 8.5. It contains two granulin domains from sequence released in the GenBank (GAA54205.1), which is presumed without N-terminal signal peptide. Multiple alignments of the sequences among GRN and nine members from other organisms (Fig. 1a) indicated that it belongs to the granulin family with a conservative domain with rich cysteine peptides. They share low sequence identity to each other except for O. viverrini. In addition, the sequence is abundant with cysteines being presumed to contain thirteen disulphide bonds. Moreover, the phylogenetic analysis (Fig. 1b) suggested that the granulin protein from C. sinensis has a very close relationship to O. viverrini. Furthermore, the evolution of the members from host and trematode or nematode may vary greatly.Fig. 1 a Multiple alignment of sequences with one core granulin domain from various species are performed with Vector NTI software. Identical sequences are in black and conservative sequences are in grey; theoretical disulphide bonds are numbered one to six above each cysteine residue. b Phylogenetic tree for the granulins from a range of phyla constructed by MEGA 6.0 using the neighbor-joining method, Poisson correction is required and bootstrap values are 1,000. The abbreviations and accession numbers of the sequences are as follows: Clonorchis sinensis (C. sinensis, GAA54205.1); Opisthorchis viverrini (O. viverrini, XP_009174632.1); Caenorhabditis elegans (C. elegans, NP_492982.1); Dicentrarchus labrax (D. labrax, CBN81737.1); Fasciola hepatica (F. hepatica, ID BN1106_s891B000441 in the WormBase ParaSite); Schistosoma japonicum (S. japonicum, CAX73857.1); Schistosoma haematobium (S. haematobium, XP_012796138.1); Homo sapiens (H. sapiens, NP_002078.1); Mus musculus (M. musculus, NP_032201.2); Rattus norvegicus (R. norvegicus, AAH72469.1); Ixodes scapularis (I. scapularis, XP_002415868.1); Trichinella spiralis (T. spiralis, XP_003371171.1); Anolis carolinensis (A. carolinensis, XP_008111426.1); Haemonchus contortus (H. contortus, CDJ86608.1), Schistosoma mansoni (S. mansoni, CCD75903.1)