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Guo H, Tan J, He Y, Yuan S, Jin K, Li Z. In Vitro Virulence Contrast of Seven Genetically Distinct Toxoplasma gondii Isolates After Rejuvenation In Vivo. Acta Parasitol 2024; 69:227-232. [PMID: 37979012 DOI: 10.1007/s11686-023-00740-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 10/26/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND In the past for more than 100 years at least 300 genotypes of Toxoplasma gondii were recorded and several traditional isolates such as RH, GT1, ME49, PRU and VEG were used repeatedly to clarify the pathogenic mechanisms and the epidemiological significance to human, but for if their virulence was mutative post-iterative passages it remains confused. OBJECTIVE Therefore, in the study, seven genetically distinct T. gondii including C7 and PYS previously discovered in China were reidentified by sequencing the head of hsp40 locus to distinguish their virulence in vitro post-rejuvenation in vivo. RESULTS Our data showed the nucleotides were different in 18 positions and 7 of them can be used to type T. gondii isolates. Total 634 plaques of T. gondii without two or more overlaps indicated that RH and GT1 tachyzoites possess stronger power than other five isolates in vitro (p < 0.001), followed by ME49, PRU, C7, PYS, and the weakest VEG. Based on the shapes of plaques, we found the ratio of their width/length was associated with the virulence of T. gondii, and speculated it could be used to judge T. gondii tachyzoites in vitro, whereas the data of simple linear regression analyses did not agree. CONCLUSIONS Together, virulence of seven genetically distinct T. gondii isolates that can be distinguished by seven mutative nucleotides in hsp40 was redefined in vitro post-rejuvenation in vivo, and it cannot be directly judged just according to the shapes of plaques formed in vitro.
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Affiliation(s)
- Haiting Guo
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, College of Basic Medicine, Guilin Medical University, Guilin, 541199, People's Republic of China
| | - Jie Tan
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, College of Basic Medicine, Guilin Medical University, Guilin, 541199, People's Republic of China
| | - Yulin He
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, College of Basic Medicine, Guilin Medical University, Guilin, 541199, People's Republic of China
| | - Shumin Yuan
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, College of Basic Medicine, Guilin Medical University, Guilin, 541199, People's Republic of China
| | - Ke Jin
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, College of Basic Medicine, Guilin Medical University, Guilin, 541199, People's Republic of China
| | - Zhongyuan Li
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, College of Basic Medicine, Guilin Medical University, Guilin, 541199, People's Republic of China.
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Colos-Arango A, Largo-de la Torre A, Calero-Bernal R, Miguel Ortega-Mora L, Regidor-Cerrillo J. Short-term culture adaptation of Toxoplasma gondii archetypal II and III field isolates affects cystogenic capabilities and modifies virulence in mice. Int J Parasitol 2023:S0020-7519(23)00074-7. [PMID: 37059167 DOI: 10.1016/j.ijpara.2023.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/28/2023] [Accepted: 03/20/2023] [Indexed: 04/16/2023]
Abstract
Most Toxoplasma gondii research has been carried out using strains maintained in the laboratory for long periods of time. Long-term passage in mice or cell culture influences T. gondii phenotypic traits such as the capability to produce oocysts in cats and virulence in mice. In this work, we investigated the effect of cell culture adaptation in the short term for recently obtained type II (TgShSp1 (Genotype ToxoDB#3), TgShSp2 (#1), TgShSp3 (#3) and TgShSp16 (#3)) and type III (#2) isolates (TgShSp24 and TgPigSp1). With this purpose, spontaneous and alkaline stress-induced cyst formation in Vero cells during 40 passages, from passage 10 (p10) to 50 (p50), and isolate virulence at p10 versus p50 were studied using a harmonized bioassay method in Swiss/CD1 mice. Toxoplasma gondii cell culture maintenance showed a drastic loss of spontaneous and induced production of mature cysts after ≈ 25-30 passages. The TgShSp1, TgShSp16 and TgShSp24 isolates failed to generate spontaneously formed mature cysts at p50. Limited cyst formation was associated with an increase in parasite growth and a shorter lytic cycle. In vitro maintenance also modified T. gondii virulence in mice at p50 with events of exacerbation, increasing cumulative morbidity for TgShSp2 and TgShSp3 isolates and mortality for TgShSp24 and TgPigSp1 isolates, or attenuation, with absence of mortality and severe clinical signs for TgShSp16, and better control of the infection with the lowest parasite and cyst burdens in lungs and brain for the TgShSp1 isolate. The present findings show deep changes in relevant phenotypic traits in laboratory-adapted T. gondii isolates and open new discussion about their use for inferring keys to parasite biology and virulence.
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Affiliation(s)
- Alicia Colos-Arango
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Andrea Largo-de la Torre
- SALUVET-Innova S.L., Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Rafael Calero-Bernal
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Javier Regidor-Cerrillo
- SALUVET-Innova S.L., Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain.
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Calero-Bernal R, Fernández-Escobar M, Katzer F, Su C, Ortega-Mora LM. Unifying Virulence Evaluation in Toxoplasma gondii: A Timely Task. Front Cell Infect Microbiol 2022; 12:868727. [PMID: 35573788 PMCID: PMC9097680 DOI: 10.3389/fcimb.2022.868727] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/28/2022] [Indexed: 01/25/2023] Open
Abstract
Toxoplasma gondii, a major zoonotic pathogen, possess a significant genetic and phenotypic diversity that have been proposed to be responsible for the variation in clinical outcomes, mainly related to reproductive failure and ocular and neurological signs. Different T. gondii haplogroups showed strong phenotypic differences in laboratory mouse infections, which provide a suitable model for mimicking acute and chronic infections. In addition, it has been observed that degrees of virulence might be related to the physiological status of the host and its genetic background. Currently, mortality rate (lethality) in outbred laboratory mice is the most significant phenotypic marker, which has been well defined for the three archetypal clonal types (I, II and III) of T. gondii; nevertheless, such a trait seems to be insufficient to discriminate between different degrees of virulence of field isolates. Many other non-lethal parameters, observed both in in vivo and in vitro experimental models, have been suggested as highly informative, yielding promising discriminatory power. Although intra-genotype variations have been observed in phenotypic characteristics, there is no clear picture of the phenotypes circulating worldwide; therefore, a global overview of T. gondii strain mortality in mice is presented here. Molecular characterization has been normalized to some extent, but this is not the case for the phenotypic characterization and definition of virulence. The present paper proposes a baseline (minimum required information) for the phenotypic characterization of T. gondii virulence and intends to highlight the needs for consistent methods when a panel of T. gondii isolates is evaluated for virulence.
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Affiliation(s)
- Rafael Calero-Bernal
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
- *Correspondence: Rafael Calero-Bernal, ; Luis Miguel Ortega-Mora,
| | - Mercedes Fernández-Escobar
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Frank Katzer
- Disease Control Department, Moredun Research Institute, Edinburgh, United Kingdom
| | - Chunlei Su
- Department of Microbiology, University of Tennessee, Knoxville, TN, United States
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
- *Correspondence: Rafael Calero-Bernal, ; Luis Miguel Ortega-Mora,
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Fernández-Escobar M, Schares G, Maksimov P, Joeres M, Ortega-Mora LM, Calero-Bernal R. Toxoplasma gondii Genotyping: A Closer Look Into Europe. Front Cell Infect Microbiol 2022; 12:842595. [PMID: 35402301 PMCID: PMC8984497 DOI: 10.3389/fcimb.2022.842595] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/25/2022] [Indexed: 01/22/2023] Open
Abstract
Toxoplasma gondii is a major zoonotic agent which may cause harmful effects mainly in pregnant and immunocompromised hosts. Despite many efforts on its genetic characterization, an entirely clear picture of the population structure in Europe has not been achieved yet. The present study aimed to summarize the available genotyping information and to map the distribution of circulating strains. There is consensus on type II T. gondii genotypes prevailing in Europe, but the absence of harmonization in the use of typing methods limits detailed knowledge. Standardized, high-end typing tools and integrative strategies are needed to fill the gaps and complete an accurate image of the T. gondii genetic population in Europe.
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Affiliation(s)
- Mercedes Fernández-Escobar
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Gereon Schares
- National Reference Laboratory for Toxoplasmosis, Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Pavlo Maksimov
- National Reference Laboratory for Toxoplasmosis, Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Maike Joeres
- National Reference Laboratory for Toxoplasmosis, Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Rafael Calero-Bernal
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
- *Correspondence: Rafael Calero-Bernal,
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Uzelac A, Klun I, Ćirković V, Bauman N, Bobić B, Štajner T, Srbljanović J, Lijeskić O, Djurković-Djaković O. Toxoplasma gondii Genotypes Circulating in Serbia-Insight into the Population Structure and Diversity of the Species in Southeastern Europe, a Region of Intercontinental Strain Exchange. Microorganisms 2021; 9:microorganisms9122526. [PMID: 34946128 PMCID: PMC8708754 DOI: 10.3390/microorganisms9122526] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/24/2021] [Accepted: 12/01/2021] [Indexed: 01/08/2023] Open
Abstract
In Europe, Toxoplasma gondii lineage II is dominant, and ToxoDB#1 the most frequently occurring genotype. The abundance of lineage III genotypes varies geographically and lineage I are rare, yet present in several regions of the continent. Data on the T. gondii population structure in southeastern Europe (SEE) are scarce, yet necessary to appreciate the diversity of the species in Europe. To help fill this gap, we genotyped 67 strains from nine species of intermediate hosts in Serbia by MnPCR-RFLP, determined the population structure, and identified the genotypes using ToxoDB. A neighbor-joining tree was also constructed from the isolates genotyped on nine loci. While 42% of the total genotype population consisted of ToxoDB#1 and ToxoDB#2, variant genotypes of both lineages comprised 46% of the population in wildlife and 28% in domestic animals and humans. One genotype of Africa 4 lineage was detected in a human sample. Interestingly, the findings include one lineage III variant and one II/III recombinant isolate with intercontinental distribution, which appear to be moderately related to South American genotypes. Based on these findings, SEE is a region of underappreciated T. gondii genetic diversity and possible strain exchange between Europe and Africa.
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Fernández-Escobar M, Calero-Bernal R, Regidor-Cerrillo J, Vallejo R, Benavides J, Collantes-Fernández E, Ortega-Mora LM. In vivo and in vitro models show unexpected degrees of virulence among Toxoplasma gondii type II and III isolates from sheep. Vet Res 2021; 52:82. [PMID: 34112256 PMCID: PMC8194156 DOI: 10.1186/s13567-021-00953-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/18/2021] [Indexed: 01/09/2023] Open
Abstract
Toxoplasma gondii is an important zoonotic agent with high genetic diversity, complex epidemiology, and variable clinical outcomes in animals and humans. In veterinary medicine, this apicomplexan parasite is considered one of the main infectious agents responsible for reproductive failure in small ruminants worldwide. The aim of this study was to phenotypically characterize 10 Spanish T. gondii isolates recently obtained from sheep in a normalized mouse model and in an ovine trophoblast cell line (AH-1) as infection target cells. The panel of isolates met selection criteria regarding such parameters as genetic diversity [types II (ToxoDB #1 and #3) and III (#2)], geographical location, and sample of origin (aborted foetal brain tissues or adult sheep myocardium). Evaluations of in vivo mortality, morbidity, parasite burden and histopathology were performed. Important variations between isolates were observed, although all isolates were classified as “nonvirulent” (< 30% cumulative mortality). The isolates TgShSp16 (#3) and TgShSp24 (#2) presented higher degrees of virulence. Significant differences were found in terms of in vitro invasion rates and tachyzoite yield at 72 h post-inoculation (hpi) between TgShSp1 and TgShSp24 isolates, which exhibited the lowest and highest rates, respectively. The study of the CS3, ROP18 and ROP5 loci allelic profiles revealed only type III alleles in ToxoDB #2 isolates and type II alleles in the #1 and #3 isolates included. We concluded that there are relevant intra- and inter-genotype virulence differences in Spanish T. gondii isolates, which could not be inferred by genetic characterization using currently described molecular markers.
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Affiliation(s)
- Mercedes Fernández-Escobar
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Rafael Calero-Bernal
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain.
| | - Javier Regidor-Cerrillo
- SALUVET-Innova S.L., Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | | | | | - Esther Collantes-Fernández
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain.
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