Bioinformatic identification of vaccine and diagnostic candidates of Cryptosporidium parvum

TOMAZIC ML; RODRIGUEZ AE; FLORIN-CHRISTENSEN M; SCHNITTGER L

Congreso; 13th International Congress of Parasitology (ICOPA); 2014

Bioinformatic identification of vaccine and diagnostic candidates of Cryptosporidium parvumBACKGROUND: Bovine cryptosporidiosis is mainly caused by the zoonoticapicomplexan Cryptosporidium parvum. The disease is responsible for a considerablemorbidity and mortality of pre-weaned calves around the world. Infected animalsexcrete large amounts of the infective stage, the oocyst, into the environment. Inhumans, the infection is known to be a major cause of infant death in developingcountries and considered emergent in industrialized ones. So far there are neither fullyeffective treatments nor vaccines available. Glycosylphosphatidylinositol (GPI)anchored proteins have been shown to be involved in invasion of protozoan parasitesand are often immunodominant. In this work we identified GPI-anchored antigens of C.parvum in order to characterize their potential as components of a subunit vaccineand/or serology-based diagnostic tools.METHODS: A reverse vaccinology approach was followed by screening the C. parvumproteome using a combination of signal peptide- and five GPI-anchor predictivebioinformatic tools. Cryptosporidium-specific antigens were determined by a reverseBLASTp procedure and the Interpro database was used to determine predictedfunctions of antigen domains.RESULTS: Of the 3805 proteins of the C. parvum proteome, altogether 13 proteinswere identified as being GPI-anchored. These proteins include GP40/15, which hasexperimentally been demonstrated to possess a GPI-anchor, supporting the validity ofour approach. Three candidates were selected based on i) the highest score ofprediction, ii) presence of a domain reported to be involved in parasite invasion, and iii)their Cryptosporidium-specificity, and recombinant forms were produced.CONCLUSIONS: Ongoing research is verifying whether selected GPI-anchoredproteins constitute valid vaccine candidates and diagnostic antigens. Financed byCONICET, INTA (PNSA-1115053) and ANPCyT (PICT2012-0695)