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Research Project: Development of Detection and Control Strategies for Bovine Babesiosis and Equine Piroplasmosis

Location: Animal Disease Research

Title: Spherical body protein 2 truncated copy 11 as a specific babesia bovis attenuation marker

Author
item Gallego-lopez, G - Washington State University
item Lau, Aot - National Instiute Of Allergy And Infectious Diseases (NIAID, NIH)
item Johnson, W Carl - Carl
item Ueti, Massaro
item Suarez, Carlos

Submitted to: Parasites & Vectors
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/6/2018
Publication Date: 3/12/2018
Citation: Gallego-Lopez, G., Lau, A., Johnson, W.C., Ueti, M.W., Suarez, C.E. 2018. Spherical body protein 2 truncated copy 11 as a specific babesia bovis attenuation marker. Parasites & Vectors. 11:169. https://doi.org/10.1186/s13071-018-2782-z.
DOI: https://doi.org/10.1186/s13071-018-2782-z

Interpretive Summary: Bovine babesiosis caused by B. bovis is a tick-borne hemoparasitic disease that affects more than 500 million cattle annually worldwide, and improved methods for control are needed. Crucial elements necessary to facilitate the development of subunit vaccines include a better understanding of the attenuation mechanisms or virulent determinants, and the identification of factors in the vaccine strains that contribute to protective immunity. If the factors involved in attenuation are identified, then a stable, live vaccine with no virulence reversion capability is possible. Spherical body protein 2 (SBP-2) truncated copies 7, 9 and 11, gene transcripts in babesia bovis, were recently reported to be significantly up-regulated in two geographically distinct attenuated B. bovis strains. In this study we confirmed that only up-regulation of the sbp2t11 gene, can be associated with an attenuated phenotype, and differentially expressed in blood stages of the parasite. The data suggests that sbp2t11 is a strong candidate as an attenuation marker for B. bovis. Identification of such markers allows future research which aims at generating genetically defined and safer vaccines against B. bovis.

Technical Abstract: Background: Spherical body protein 2 (SBP-2) truncated copies 7, 9 and 11, gene transcripts in Babesia bovis, were recently reported to be significantly up-regulated in two geographically distinct attenuated B. bovis strains. Results: Sequence comparisons between the sbp2t7, 9 and 11 genes among geographically distinct strains show a lack of strict sequence conservation in all three genes. Comparisons among the three sbp-2 genes transcript levels of distinct virulent-attenuated B. bovis strain pairs confirmed that only up-regulation of the sbp2t11 gene, can be associated with an attenuated phenotype. In addition, sbp2t11 transcript level is correlated with SBP2t11 expression in both Texas attenuated and virulent strains of B. bovis and that sbp2t11 is differentially expressed in the blood stages of the parasite but is undetectable in the kinete stages. This latter result suggests that sbp2t11 may have a role in the infection of erythrocytes. Conclusions: Sbp2t11 shows a consistent pattern of up-regulation in multiple attenuated strains when compared to their virulent parental strains, and thus it is a strong candidate as an attenuation marker for B. bovis. Identification of such markers allows future research which aims at generating genetically defined and safer vaccines against B. bovis.