Major Surface Antigens in Zoonotic Babesia

Abstract

Human babesiosis results from a combination of tick tropism for humans, susceptibility of a host to sustain Babesia development, and contact with infected ticks. Climate modifications and increasing diagnostics have led to an expanded number of Babesia species responsible for human babesiosis, although, to date, most cases have been attributed to B. microti and B. divergens. These two species have been extensively studied, and in this review, we mostly focus on the antigens involved in host–parasite interactions. We present features of the major antigens, so-called Bd37 in B. divergens and BmSA1/GPI12 in B. microti, and highlight the roles of these antigens in both host cell invasion and immune response. A comparison of these antigens with the major antigens found in some other Apicomplexa species emphasizes the importance of glycosylphosphatidylinositol-anchored proteins in host–parasite relationships. GPI-anchor cleavage, which is a property of such antigens, leads to soluble and membrane-bound forms of these proteins, with potentially differential recognition by the host immune system. This mechanism is discussed as the structural basis for the protein-embedded immune escape mechanism. In conclusion, the potential consequences of such a mechanism on the management of both human and animal babesiosis is examined.

Identification and characterization of extracellular vesicles from red cells infected with Babesia divergens and Babesia microti

“…To obtain an idea of the proportion of EVs that are sourced from Babesia infection, we decided to use parasite markers to differentiate between EVs from uninfected versus iRBCs in both B. divergens and B. microti infection models. To identify B. divergens-specific EVs, we used antibodies against Bd37, which is an abundant 37-kDa protein from B. divergens (Delbecq, 2022). To identify B. microti-specific EVs, we used antibodies against BMN-2, which is an abundant protein from B. microti (Homer et al, 2000) (Elton et al, 2019).…”

Global Metabolomic Profiling of Host Red Blood Cells Infected with Babesia divergens Reveals Novel Antiparasitic Target Pathways

“…To assess whether the loss of free fatty acids resulted in defective merozoite membrane genesis, we used Bd37 as a marker to examine the merozoite membranes. Bd37 is the major surface antigen of B. divergens and has been shown to be glycosylphosphatidylinositol (GPI) anchored at the surface of the merozoite ( 62 – 64 ).…”

Histopathological Analysis of Selected Organs of Rats with Congenital Babesiosis Caused by Babesia microti

“…A lot of unknown facts remain regarding the tropism of different species of the genus Babesia to erythrocytes, the diversity of Babesia spp. antigens, and information regarding the molecular effects of Babesia microti on cells of different organs [32,33].…”