Babesia bovis biological clones and the inter-strain allelic diversity of the Bv80 gene support subpopulation selection as a mechanism involved in the attenuation of two virulent isolates

Baravalle, María Eugenia; Thompson, Carolina S.; Valentini, Beatriz; Ferreira, Mariano B; Echaide, Susana Torioni de; Christensen, Magnus; Echaide, Ignacio

doi:10.1016/j.vetpar.2012.06.037

Cited by 17 publications

(19 citation statements)

References 36 publications

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“…Two closely-sized alleles (421 bp and 426 bp) were detected by marker MSC08 and a heterozygosity of 0.262 was calculated for this marker alone ( Supplementary Table S5). Shifts in dominant populations have been previously reported during the attenuation and mass production of vaccine cell lines (Baravalle et al, 2012;Mazuz et al, 2012). However, in this case, the vaccine clones are identical at all other loci and the most parsimonious explanation it that this locus has experienced a relatively recent de novo mutation and that the original vaccine genotype was indeed a haploid clone.…”

Section: Discussionmentioning

confidence: 63%

Infection dynamics of Theileria annulata over a disease season following cell line vaccination

Bilgiç

Aksulu

Bakırcı

et al. 2019

Veterinary Parasitology

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Tropical theileriosis is a tick-borne haemoparasitic disease of cattle caused by the protozoan parasite Theileria annulata. Globally, the economic impact of the disease is immense and enhanced control measures would improve livestock production in endemic regions. Immunisation with a live attenuated vaccine is an effective and widely used control method, however, the repeated use of live vaccines may have an impact on the field parasite population at a genetic level. Additionally, there has been an increasing number of reports of vaccine breakthrough cases in recent years. Thus, the present study was designed to evaluate the genetic composition of a parasite population over a disease season in a locality where live cell line vaccination is practised. A diverse range of parasite genotypes was identified and every T. annulata positive cattle blood sample harboured multiple parasite genotypes. An alteration in the major genotype and an increasing multiplicity of infection in individual animals was observed over the course of the disease season. Vaccination status was found not to effect within-host multiplicity of infection, while a significantly higher number of genotypes was detected in grazed cattle compared to non-grazed ones. A degree of genetic isolation was evident between parasite populations on a micro-geographic scale, which has not been reported previously for T. annulata. Analysis of parasite genotypes in vaccinated animals suggested only a transient effect of the vaccine genotype on the genetic diversity of the T. annulata population. The vaccine genotype was not detected among clones of two vaccine 'breakthrough' isolates and there is no suggestion that it was responsible for disease. The obtained data indicated that in the system studied there is no apparent risk of introducing the vaccine genotype into the population with only a transient effect on the genetic diversity of the parasite population during the disease season.

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Section: Discussionmentioning

confidence: 63%

Infection dynamics of Theileria annulata over a disease season following cell line vaccination

Bilgiç

Aksulu

Bakırcı

et al. 2019

Veterinary Parasitology

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“…This observation is in line with recent reports were parasite attenuation was found to be associated with a strong overall reduction in genome diversity, as well as a reduced diversity of the variant erythrocyte surface 1 ( ves ) multigene family (Lau et al., ). It has been suggested that subpopulation selection may be a mechanism of attenuation (Baravalle et al., ). However, as determined by sequencing of the polymorphic Bv80 gene, Mazuz et al.…”

Section: Resultsmentioning

confidence: 99%

Evidence for Extensive Genetic Diversity and Substructuring of theBabesia bovisMetapopulation

Flores¹,

Minichiello²,

Araújo

et al. 2013

Transbound Emerg Dis

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SummaryBabesia bovis is a tick-transmitted haemoprotozoan and a causative agent of bovine babesiosis, a cattle disease that causes significant economic loss in tropical and subtropical regions. A panel of nineteen micro-and minisatellite markers was used to estimate population genetic parameters of eighteen parasite isolates originating from different continents, countries and geographic regions including North America (Mexico, USA), South America (Argentina, Brazil), the Middle East (Israel) and Australia. For eleven of the eighteen isolates, a unique haplotype was inferred suggesting selection of a single genotype by either in vitro cultivation or amplification in splenectomized calves. Furthermore, a high genetic diversity (H = 0.780) over all marker loci was estimated. Linkage disequilibrium was observed in the total study group but also in sample subgroups from the Americas, Brazil, and Israel and Australia. In contrast, corresponding to their more confined geographic origin, samples from Israel and Argentina were each found to be in equilibrium suggestive of random mating and frequent genetic exchange. The genetic differentiation (F ST ) of the total study group over all nineteen loci was estimated by analysis of variance (Θ) and Nei's estimation of heterozygosity (G ST' ) as 0.296 and 0.312, respectively. Thus, about 30% of the genetic diversity of the parasite population is associated with genetic differences between parasite isolates sampled from the different geographic regions. The pairwise similarity of multilocus genotypes (MLGs) was assessed and a neighbour-joining dendrogram generated. MLGs were found to cluster according to the country/continent of origin of isolates, but did not distinguish the attenuated from the pathogenic parasite state. The distant geographic origin of the isolates studied allows an initial glimpse into the large extent of genetic diversity and differentiation of the B. bovis population on a global scale.

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“…DNA was purified from 900 μL of A. marginale-infected blood [25]. Briefly, erythrocytes were lysed with erythrocyte lysis buffer (0.14 M NH 4 Cl, 0.17 M Tris-HCl) and the hemoglobin was eliminated by washes with distilled water.…”

Section: Genomic Dnamentioning

confidence: 99%

A vaccine using Anaplasma marginale subdominant type IV secretion system recombinant proteins was not protective against a virulent challenge

et al. 2020

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Anaplasma marginale is the most prevalent tick-borne livestock pathogen with worldwide distribution. Bovine anaplasmosis is a significant threat to cattle industry. Anaplasmosis outbreaks in endemic areas are prevented via vaccination with live A. centrale produced in splenectomized calves. Since A. centrale live vaccine can carry other pathogens and cause disease in adult cattle, research efforts are directed to develop safe recombinant subunit vaccines. Previous work found that the subdominant proteins of A. marginale type IV secretion system (T4SS) and the subdominant elongation factor-Tu (Ef-Tu) were involved in the protective immunity against the experimental challenge in cattle immunized with the A. marginale outer membrane (OM). This study evaluated the immunogenicity and protection conferred by recombinant VirB9.1, VirB9.2, VirB10, VirB11, and Ef-Tu proteins cloned and expressed in E. coli. Twenty steers were randomly clustered into four groups (G) of five animals each. Cattle from G1 and G2 were immunized with a mixture of 50 μg of each recombinant protein with Quil A ® or Montanide™ adjuvants, respectively. Cattle from G3 and G4 (controls) were immunized with Quil A and Montanide adjuvants, respectively. Cattle received four immunizations at three-week intervals and were challenged with 10 7 A. marginale-parasitized erythrocytes 42 days after the fourth immunization. After challenge, all cattle showed clinical signs, with a significant drop of packed cell volume and a significant increase of parasitized erythrocytes (p<0.05), requiring treatment with oxytetracycline to prevent death. The levels of IgG2 induced in the immunized groups did not correlate with the observed lack of protection. Additional strategies are required to evaluate the role of these proteins and their potential utility in the development of effective vaccines.

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Babesia bovis biological clones and the inter-strain allelic diversity of the Bv80 gene support subpopulation selection as a mechanism involved in the attenuation of two virulent isolates

Cited by 17 publications

References 36 publications

Infection dynamics of Theileria annulata over a disease season following cell line vaccination

Infection dynamics of Theileria annulata over a disease season following cell line vaccination

Evidence for Extensive Genetic Diversity and Substructuring of theBabesia bovisMetapopulation

A vaccine using Anaplasma marginale subdominant type IV secretion system recombinant proteins was not protective against a virulent challenge

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