CHARACTERIZATION OF THE PERFORIN-LIKE PROTEIN FAMILY IN Babesia sp.

PAOLETTA M; JARAMILLO ORTIZ J; LOPEZ ARIAS L; MONTENEGRO, VALERIA NOELY; FARBER M; WILKOWSKY S

Woods Hole, Massachussets

Simposio; 2018 (29th) Annual Molecular Parasitology Meeting; 2018

Marine Biological Laboratory, University of Chicago

Bovine babesiosis is a tick-borne disease caused by protozoan parasites of the Babesia genus that affects livestock production worldwide. The study of proteins involved in parasite virulence is of special interest to understand the molecular basis of host-pathogen interaction and to develop better strategies to control the disease. The aim of this study was to characterize the Perforin-Like Protein (PLP) family of Babesia sp. These pore-forming proteins have not been characterized in the Babesia genera yet and its role could be critical for pathogenesis in a similar way of what was already demonstrated in related apicomplexan organisms . In this work we have identified by bioinformatics the plp genes in the genomes of different Babesia species through detection of conserved motifs and domains. Six plp genes were found in B. bovis, B. ovata and B. microti, while 8 genes were found in B. bigemina and B. divergens. Phylogenetic analyses showed that pore-forming domains (MACPF) are highly conserved among Babesia species. Prediction of tertiary structure revealed conformational conservation with other proteins of the PLP family, suggesting similar functions with orthologs in the Apicomplexa phylum. Analysis of available transcriptomic data of 2 B. bovis strains of contrasting phenotype showed that all plp genes are transcribed. The plp1 protein has the highest expression level and is the only plp protein differentially expressed between attenuated and virulent strains. Western blot analysis of the recombinant MACPF domain of PLP1 shows that naturally infected bovine sera specifically recognize this domain confirming its immunodominance during natural infection. The hemolytic activity of the MACPF domain was confirmed through erythrocyte lysis assays, supporting its role in pathogenesis. Future work will be aimed to generate a plp1 knock-out B. bovis strain to determine the role of BboPLP1 in the parasite?s virulence.