Proteomic characterization of Babesia divergens extracellular vesicles

Protozoan parasites of the genus Babesia are considered a serious threat to humans and animals worldwide. Babesia parasites are naturally transmitted by ticks and infect the erythrocytes or red blood cells (RBCs) of many vertebrates causing babesiosis. Infectious species include B. divergens, which causes asymptomatic to fatal babesiosis in humans and red water fever in cattle in Europe. To better understand the biology of B. divergens and to develop diagnostic and control strategies for babesiosis, we studied the extracellular vesicles (EVs) released into the environment by B. divergens-infected red blood cells (iRBCs). B. divergens parasites were cultured in human erythrocytes in vitro in a complete medium containing low human vesicle (LHV) serum. Uninfected erythrocytes (uRBC) were also maintained in the LHV complete medium. Bd-derived EVs and uRBC-derived EVs were collected and purified from the supernatants of B. divergens and uRBC cultures, respectively. Proteins were extracted from Bd-derived EVs and uRBC-derived EVs.