Browsing by Author "Tārs, Kaspars"

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    Evaluation of Outer Surface Protein Vaccine Candidates of Borrelia burgdorferi for Lyme Disease
    (2023-12) Liekniņa, Ilva; Kozlova, Anna; Šaško, Marina; Akopjana, Ināra; Brangulis, Kalvis; Tārs, Kaspars
    Lyme disease affects several hundred thousand people worldwide annually, yet there is no registered vaccine for the disease available for human use. The disease is caused by Borrelia burgdorferi sensu lato complex bacteria, which harbor numerous outer surface proteins, and many of which have been targeted for vaccine development. However, to effectively combat various Borrelia species, the target protein should ideally be conserved and located in the chromosome. In this study, we evaluated the potential of seven conservative, chromosome-encoded outer surface proteins as vaccine candidates. Unfortunately, four of the initial candidates could not be produced in E. coli. The remaining BB0028, BB0158, and BB0689 proteins were administered to mice in both the free form and as conjugates with virus-like particles (VLPs). In most cases, high antibody titers were obtained, confirming the good immunogenicity of the selected proteins. However, for BB0158 and BB0689 proteins, adverse effects were observed following the injection of free proteins, which were not observed when they were coupled to VLPs. Bactericidity tests of the obtained antibodies suggested that none of the vaccine candidates could induce the production of bactericidal antibodies.
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    Structural and functional analysis of bba03, borrelia burgdorferi competitive advantage promoting outer surface lipoprotein
    (2020-10) Fridmanis, Jēkabs; Bobrovs, Raitis; Brangulis, Kalvis; Tārs, Kaspars; Jaudzems, Kristaps; Department of Human Physiology and Biochemistry
    BBA03 is a Borrelia burgdorferi outer surface lipoprotein encoded on one of the most conserved plasmids in Borrelia genome, linear plasmid 54 (lp54). Although many of its genes have been identified as contributing or essential for spirochete fitness in vivo, the majority of the proteins encoded on this plasmid have no known function and lack homologs in other organisms. In this paper, we report the solution NMR structure of the B. burgdorferi outer surface lipoprotein BBA03, which is known to provide a competitive advantage to the bacteria during the transmission from tick vector to mammalian host. BBA03 shows structural homology to other outer surface lipoproteins reflecting their genetic and evolutionary relatedness. Analysis of the structure reveals a pore in BBA03, which could potentially bind lipids.