theileri gained about 20%, which were similar to those of T. cruzi in the study by Rodríguez et al. (1996), but lower than those in the study by Rubin-de-Celis et al. (2006) (40%). Although the reason for this disparity is unclear and needs to be addressed, the attachment and invasion rates of SVEC were significantly lower than those of other cell lines. Even though no experimental rodent model has been established, in order to investigate T. PARP inhibitor theileri invasion in vivo we tried to

establish such a model. Unfortunately, we observed no clinical signs, pathologic changes or deaths (data not shown). To date, development of vaccines against trypanosomes has mainly involved exploring candidate antigens which are expressed on the surface of the parasite. Several molecules of T. cruzi have been hypothesized to interact with the host cells, including gp30, gp 35/50, penetrin (gp60), gp63, gp82, gp83, gp85, gp90, Rapamycin mucins/trans-sialidase, secreted sialidase (SAPA), mucin p45, cruzipain, oligopeptidase

B, casein kinase II substrate (TC1), LYT1 protein and prolyl oligopeptidase (POP). It is known that some of them can bind to specific receptors present in the host cell; for example, cytokeratin 18, laminin, galectin-3, fibronectin, integrins, sialic acid, TGF-β receptor, bradykinin receptors, nerve growth factor receptors (TrkA and TrkC), toll-like receptors and low density lipoprotein receptors (review by de Souza et al., 2010 and Nagajyothi et al., 2011). Nevertheless, thus far no surface molecules of T. theileri have been identified. Besides the above mentioned molecules, caveolae and lipid rafts in the host cell membrane have also been shown to take part in T. cruzi invasion. The host cell GM1 ganglioside,

a marker for lipid rafts, is enriched at the invasion site. Experimentally, colocalization between a specific GM1 probe (CTX-B) and an intracellular parasite suggest a participation of membrane rafts in the trypomastigote enough internalization. Pre-treatment with agents to disrupt membrane rafts significantly interfered with the adhesion of trypomastigotes to the macrophage surface ( Fernandes et al., 2007 and Barrias et al., 2007). Herein, lipid rafts enrichment in the early stage of invasion was first revealed in T. theileri. However, further blockage experiments are required to reconfirm this interaction effect. Cathepsin L-like (CATL) cysteine proteases play crucial functions in differentiation, multiplication and infectivity in trypanosomes. Cruzipain activates bradykinin signaling to promote Ca2+ release from endoplasmic reticulum (Scharfstein et al., 2000). CatL-like isoforms of T. cruzi (cruzipain), which is the archetype of a multigene family, have been described in T. b. brucei (brucipain), T. b. rhodesiense (rhodesain), T. congolense (congopain), and T. rangeli (rangelipain) ( Scharfstein et al., 2000). Cluster analysis of T.