ArticleVaccine2018
Genomic evidence that the live Chlamydia abortus vaccine strain 1B is not attenuated and has the potential to cause disease.
Article in Vaccine, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 21 papers.
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The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
21 citing papers in PubMed, 49 citations in OpenAlex.
- Assessment of seroprevalence and associated risk factors ofOpen veterinary journal · 2025Article
- Effects of Different Adjuvants on the Protective Efficacy of a Subcellular Vaccine AgainstVaccines · 2025Article
- Chlamydiosis in Animals.Animals : an open access journal from MDPI · 2024Review
- Evaluation of the Protective Efficacy of Different Doses of aAnimals : an open access journal from MDPI · 2024Article
- Surface Display of Cholera Toxin B Subunit RecombinantMicroorganisms · 2024Article
- Preclinical screen for protection efficacy of chlamydial antigens that are immunogenic in humans.Infection and immunity · 2023Article
- Seroprevalence and Risk Factors ofAnimals : an open access journal from MDPI · 2023Article
- Recent advances in genetic systems in obligate intracellular human-pathogenic bacteria.Frontiers in cellular and infection microbiology · 2023Review
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- Article
- Recent advances and public health implications for environmental exposure to Chlamydia abortus: from enzootic to zoonotic disease.Veterinary research · 2022Review
- Efficacy of TwoVaccines · 2021Article
- Complete Genome Sequence of Chlamydia abortus MRI-10/19, Isolated from a Sheep Vaccinated with the Commercial LiveMicrobiology resource announcements · 2021Article
- Distribution and Severity of Placental Lesions Caused by thePathogens (Basel, Switzerland) · 2021Article
- Whole genome de novo sequencing and comparative genomic analyses suggests that Chlamydia psittaci strain 84/2334 should be reclassified as Chlamydia abortus species.BMC genomics · 2021Article
- Cellular Basis for the Enhanced Efficacy of the Fms-Like Tyrosine Kinase 3 Ligand (FL) Adjuvanted VCG-BasedFrontiers in immunology · 2021Article
- Defining immune correlates during latent and active chlamydial infection in sheep.Veterinary research · 2020Article
- The 1B vaccine strain of Chlamydia abortus produces placental pathology indistinguishable from a wild type infection.PloS one · 2020Article
- Evaluation of the Efficacy of a New Commercially Available Inactivated Vaccine Against Ovine Enzootic Abortion.Frontiers in veterinary science · 2020Article
- Mini Review: Antimicrobial Control of Chlamydial Infections in Animals: Current Practices and Issues.Frontiers in microbiology · 2019Article
Corrections and comments
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Authors and funding
8 authors at 4 institutions in 3 countries.
Funding
Abstract
backgroundThe live, temperature-attenuated vaccine strain 1B of Chlamydia abortus, the aetiological agent of ovine enzootic abortion (OEA), has been implicated in cases of vaccine breakdown. The aim of this study was to understand the nature of this attenuation through sequencing of the vaccine parent strain (AB7) and the derived mutant strains 1B and 1H, as well as to clarify the role of the vaccine strain in causing disease through comparative whole genome analysis.
methodsWhole genome sequencing was performed on: vaccine parent strain AB7; N-methyl-N'-nitro-N-nitrosoguanidine (NTG)-induced temperature attenuated mutant strain 1B grown from the commercial live vaccines Cevac Chlamydia and Enzovax; strain 1H a reverted NTG mutant; and 5 strains isolated from cases of OEA originating from animals from the original vaccine safety trial (2 strains) or from vaccinated ewes or ewes exposed to vaccinated animals (3 strains).
resultsWe confirmed that AB7 is in a different lineage from the reference strain S26/3. The genome of vaccine strain 1B contains ten single nucleotide polymorphisms (SNPs) created by the NTG treatment, which are identical to those found in strain 1H. The strains from OEA cases also cluster phylogenetically very tightly with these vaccine strains.
conclusionsThe results show that C. abortus vaccine strain 1B has an identical genome sequence to the non-attenuated "reverted mutant" strain 1H. Thus, the protection of the 1B vaccine is unlikely to be due to the NTG induced SNPs and is more likely caused by the administration of high doses of C. abortus elementary bodies that stimulate protective immunity. Vaccine-identical strains were also isolated from cases of disease, as well as strains which had acquired 1-3 SNPs, including an animal that had not been vaccinated with either of the commercial live OEA vaccines, indicating that the 1B vaccine strain may be circulating and causing disease.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.