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Xu Q, Liu S, Kassegne K, Yang B, Lu J, Sun Y, Zhong W, Zhang M, Liu Y, Zhu G, Cao J, Cheng Y. Genetic diversity and immunogenicity of the merozoite surface protein 1 C-terminal 19-kDa fragment of Plasmodium ovale imported from Africa into China. Parasit Vectors 2021; 14:583. [PMID: 34819151 PMCID: PMC8611641 DOI: 10.1186/s13071-021-05086-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/03/2021] [Indexed: 11/10/2022] Open
Abstract
Background Merozoite surface protein 1 (MSP1) plays an essential role in erythrocyte invasion by malaria parasites. The C-terminal 19-kDa region of MSP1 has long been considered one of the major candidate antigens for a malaria blood-stage vaccine against Plasmodium falciparum. However, there is limited information on the C-terminal 19-kDa region of Plasmodium ovale MSP1 (PoMSP119). This study aims to analyze the genetic diversity and immunogenicity of PoMSP119. Methods A total of 37 clinical Plasmodium ovale isolates including Plasmodium ovale curtisi and Plasmodium ovale wallikeri imported from Africa into China and collected during the period 2012–2016 were used. Genomic DNA was used to amplify P. ovale curtisi (poc) msp119 (pocmsp119) and P. ovale wallikeri (pow) msp119 (powmsp119) genes by polymerase chain reaction. The genetic diversity of pomsp119 was analyzed using the GeneDoc version 6 programs. Recombinant PoMSP119 (rPoMSP119)-glutathione S-transferase (GST) proteins were expressed in an Escherichia coli expression system and analyzed by western blot. Immune responses in BALB/c mice immunized with rPoMSP119-GST were determined using enzyme-linked immunosorbent assay. In addition, antigen-specific T cell responses were assessed by lymphocyte proliferation assays. A total of 49 serum samples from healthy individuals and individuals infected with P. ovale were used for the evaluation of natural immune responses by using protein microarrays. Results Sequences of pomsp119 were found to be thoroughly conserved in all the clinical isolates. rPoMSP119 proteins were efficiently expressed and purified as ~ 37-kDa proteins. High antibody responses in mice immunized with rPoMSP119-GST were observed. rPoMSP119-GST induced high avidity indexes, with an average of 92.57% and 85.32% for rPocMSP119 and rPowMSP119, respectively. Cross-reactivity between rPocMSP119 and rPowMSP119 was observed. Cellular immune responses to rPocMSP119 (69.51%) and rPowMSP119 (52.17%) induced in rPocMSP119- and rPowMSP119-immunized mice were found in the splenocyte proliferation assays. The sensitivity and specificity of rPoMSP119-GST proteins for the detection of natural immune responses in patients infected with P. ovale were 89.96% and 75%, respectively. Conclusions This study revealed highly conserved gene sequences of pomsp119. In addition, naturally acquired humoral immune responses against rPoMSP1 were observed in P. ovale infections, and high immunogenicity of rPoMSP119 in mice was also identified. These instructive findings should encourage further testing of PoMSP119 for rational vaccine design. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-05086-6.
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Affiliation(s)
- Qinwen Xu
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Sihong Liu
- Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, 214064, Jiangsu, People's Republic of China
| | - Kokouvi Kassegne
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, People's Republic of China
| | - Bo Yang
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Jiachen Lu
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Yifan Sun
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Wenli Zhong
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Miaosa Zhang
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Yaobao Liu
- Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, 214064, Jiangsu, People's Republic of China
| | - Guoding Zhu
- Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, 214064, Jiangsu, People's Republic of China
| | - Jun Cao
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China. .,Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, 214064, Jiangsu, People's Republic of China.
| | - Yang Cheng
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China.
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Oyedeji SI, Awobode HO, Ojurongbe O, Anumudu C, Bassi PU. Molecular Identification and Characterization of Plasmodium ovale curtisi in Field Isolates from Symptomatic Children in North-Central Nigeria. Acta Parasitol 2021; 66:915-924. [PMID: 33710479 DOI: 10.1007/s11686-021-00350-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 02/10/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE Plasmodium ovale is not usually the focus of most malaria research or intervention programmes and has lately been termed the neglected human malaria parasites. The parasite exists as two genetically distinct sympatric species namely P. ovale curtisi and P. ovale wallikeri but information on the distribution of P. ovale sub-species is lacking in Nigeria. The objective of this study, therefore, was aimed at characterizing the P. ovale sub-species in isolates from symptomatic individuals in North-central Nigeria. METHODS Parasites were identified by light microscopy of Giemsa stained thick and thin blood films. Molecular characterization and confirmation of P. ovale sub-species were done by species-specific nested PCR and sequencing of the small subunit ribosomal RNA (SSUrRNA) gene. RESULTS A total of 412 children were enrolled into this study of which 88.6% (n = 365) were positive for Plasmodium species by nested PCR and P. falciparum was predominant. Of the 365 isolates, 4 (1.1%) had P. ovale infections and of these, 3 (0.8%) were mixed species infections of P. ovale with P. falciparum. DNA sequence analysis confirmed that all the four P. ovale parasites were P. ovale curtisi as their sequences were 99-100% identical to previously published P. ovale curtisi sequences in the GenBank and they cluster with the P. ovale curtisi sequences by phylogeny. CONCLUSION Our findings demonstrate the occurrence of P. ovale curtisi in the study area. This has implications for public health and malaria elimination programmes, since they also serve as potential risk to travellers from malaria-free regions.
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Affiliation(s)
- Segun Isaac Oyedeji
- Molecular Parasitology and Genetics Unit, Department of Animal and Environmental Biology, Federal University Oye-Ekiti, Oye-Ekiti, Nigeria.
| | | | - Olusola Ojurongbe
- Department of Medical Microbiology and Parasitology, Ladoke Akintola University of Technology, Osogbo, Nigeria
| | - Chiaka Anumudu
- Parasitology Unit, Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Peter Usman Bassi
- Department of Clinical Pharmacology and Therapeutics, University of Abuja, Abuja, Nigeria
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Yang B, Liu H, Xu QW, Sun YF, Xu S, Zhang H, Tang JX, Zhu GD, Liu YB, Cao J, Cheng Y. Genetic Diversity Analysis of Surface-Related Antigen (SRA) in Plasmodium falciparum Imported From Africa to China. Front Genet 2021; 12:688606. [PMID: 34421996 PMCID: PMC8378275 DOI: 10.3389/fgene.2021.688606] [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: 03/31/2021] [Accepted: 07/01/2021] [Indexed: 11/13/2022] Open
Abstract
Plasmodium falciparum surface-related antigen (SRA) is located on the surfaces of gametocyte and merozoite and has the structural and functional characteristics of potential targets for multistage vaccine development. However, little information is available regarding the genetic polymorphism of pfsra. To determine the extent of genetic variation about P. falciparum by characterizing the sra sequence, 74 P. falciparum samples were collected from migrant workers who returned to China from 12 countries of Africa between 2015 and 2019. The full length of the sra gene was amplified and sequenced. The average pairwise nucleotide diversities (π) of P. falciparum sra gene was 0.00132, and the haplotype diversity (Hd) was 0.770. The average number of nucleotide differences (k) for pfsra was 3.049. The ratio of non-synonymous (dN) to synonymous (dS) substitutions across sites (dN/dS) was 1.365. Amino acid substitutions of P. falciparum SRA could be categorized into 35 unique amino acid variants. Neutrality tests showed that the polymorphism of PfSRA was maintained by positive diversifying selection, which indicated its role as a potential target of protective immune responses and a vaccine candidate. Overall, the ability of the N-terminal of PfSRA antibodies to evoke inhibition of merozoite invasion of erythrocytes and conserved amino acid at low genetic diversity suggest that the N-terminal of PfSRA could be evaluated as a vaccine candidate against P. falciparum infection.
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Affiliation(s)
- Bo Yang
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Hong Liu
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
| | - Qin-Wen Xu
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Yi-Fan Sun
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Sui Xu
- Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, China
| | - Hao Zhang
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Jian-Xia Tang
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China.,Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, China
| | - Guo-Ding Zhu
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China.,Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, China
| | - Yao-Bao Liu
- Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China.,Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, China
| | - Jun Cao
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, China.,Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China.,Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, China
| | - Yang Cheng
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, China
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Mahittikorn A, Masangkay FR, Kotepui KU, Milanez GDJ, Kotepui M. Comparison of Plasmodium ovale curtisi and Plasmodium ovale wallikeri infections by a meta-analysis approach. Sci Rep 2021; 11:6409. [PMID: 33742015 PMCID: PMC7979700 DOI: 10.1038/s41598-021-85398-w] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 03/02/2021] [Indexed: 12/12/2022] Open
Abstract
Malaria caused by Plasmodium ovale species is considered a neglected tropical disease with limited information about its characteristics. It also remains unclear whether the two distinct species P. ovale curtisi and P. ovale wallikeri exhibit differences in their prevalence, geographic distribution, clinical characteristics, or laboratory parameters. Therefore, this study was conducted to clarify these differences to support global malaria control and eradication programs. Studies reporting the occurrence of P. ovale curtisi and P. ovale wallikeri were explored in databases. Differences in proportion, clinical data, and laboratory parameters between the two species were estimated using a random-effects model and expressed as pooled odds ratios (ORs), mean difference (MD), or standardized MD depending on the types of extracted data. The difference in geographical distribution was visualized by mapping the origin of the two species. A total of 1453 P. ovale cases extracted from 35 studies were included in the meta-analysis. The p-value in the meta-analyses provided evidence favoring a real difference between P. ovale curtisi malaria cases (809/1453, 55.7%) and P. ovale wallikeri malaria cases (644/1453, 44.3%) (p: 0.01, OR 1.61, 95% CI 0.71-3.63, I2: 77%). Subgroup analyses established evidence favoring a real difference between P. ovale curtisi and P. ovale wallikeri malaria cases among the imported cases (p: 0.02, 1135 cases). The p value in the meta-analyses provided evidence favoring a real difference in the mean latency period between P. ovale curtisi (289 cases) and P. ovale wallikeri malaria (266 cases) (p: 0.03, MD: 27.59, 95% CI 1.99-53.2, I2: 94%), total leukocyte count (p < 0.0001, MD: 840, 95% CI 610-1070, I2: 0%, two studies) and platelet count (p < 0.0001, MD: 44,750, 95% CI 2900-60,500, I2: 32%, three studies). Four continents were found to have reports of P. ovale spp., among which Africa had the highest number of reports for both P. ovale spp. in its 37 countries, with a global proportion of 94.46%, and an almost equal distribution of both P. ovale spp., where P. ovale curtisi and P. ovale wallikeri reflected 53.09% and 46.90% of the continent's proportion, respectively. This is the first systematic review and meta-analysis to demonstrate the differences in the characteristics of the two distinct P. ovale species. Malaria caused by P. ovale curtisi was found in higher proportions among imported cases and had longer latency periods, higher platelet counts, and higher total leukocyte counts than malaria caused by P. ovale wallikeri. Further studies with a larger sample size are required to confirm the differences or similarities between these two species to promote malaria control and effective eradication programs.
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Affiliation(s)
- Aongart Mahittikorn
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Frederick Ramirez Masangkay
- Department of Medical Technology, Institute of Arts and Sciences, Far Eastern University-Manila, Manila, Philippines
| | - Kwuntida Uthaisar Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand
| | - Giovanni De Jesus Milanez
- Department of Medical Technology, Institute of Arts and Sciences, Far Eastern University-Manila, Manila, Philippines
| | - Manas Kotepui
- Medical Technology, School of Allied Health Sciences, Walailak University, Tha Sala, Nakhon Si Thammarat, Thailand.
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Lei Y, Shen F, Zhu H, Zhu L, Chu R, Tang J, Yao W, Zhu G, Zhang D, Cao J, Cheng Y. Low genetic diversity and strong immunogenicity within the apical membrane antigen-1 of plasmodium ovale spp. imported from africa to china. Acta Trop 2020; 210:105591. [PMID: 32562621 PMCID: PMC7456792 DOI: 10.1016/j.actatropica.2020.105591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 06/16/2020] [Accepted: 06/16/2020] [Indexed: 10/27/2022]
Abstract
Malaria is still an important challenge for global public health because of its extensive mortality and morbidity. Plasmodium ovale is mainly distributed in tropical regions of Africa and Asia. it includes two distinct ovale malaria species, which are P. ovale curtisi and P. ovale wallikeri. Apical membrane antigen-1 (AMA-1) is an asexual blood-stage protein which is essential for Plasmodium. Thus far, no study on gene polymorphism and immunogenicity of P. ovale AMA-1 (PoAMA-1) has been conducted. Amplified poama1 gene products from 14 P ovale curtisi samples and 12 P ovale wallikeri samples imported from Africa to Jiangsu Province, China were sequenced and their polymorphisms were analyzed. We expressed recombinant PoAMA-1 (rPoAMA-1, 53 kDa) proteins in an E. coli expression system and evaluated immune responses against the rPoAMA-1 in BALB/c mice. We identified a synonymous mutation in nucleotide position 333 of the pocama-1 gene and powama-1 did not reveal any variation. The humoral and cellular immune responses to rPoAMA-1 were evaluated using enzyme-linked immunosorbent assay (ELISA) and flow cytometry. rPoAMA-1-immunized mice produced specific antibodies as verified by immunoblotting. The rPoAMA-1 induced high antibody titers (1: 640,000), and had high avidity indexes (an average of 78.63% and 83.40%). The antibodies also recognized the native proteins, namely, crude antigen from blood stages. Cross-reactivity between rPocAMA-1 and rPowAMA-1 was observed. Moreover, rPoAMA-1 s induced interferon (IFN)-gamma-secreting cells in mice and increased lymphocyte proliferation response. Low genetic diversity was observed in poama-1 from the Jiangsu Province imported malaria cases, and further studies conclusively showed its strong immunogenicity. Significant cross-reactivity was found between rPocAMA-1 and rPowAMA-1, suggesting that a single PoAMA-1 antigen could be used to diagnose P. ovale curtisi or P. ovale wallikeri patient simultaneously. However, further evaluation needs to be carried out to validate the potential and limitations of PoAMA-1 as a candidate vaccine.
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Uwase J, Chu R, Kassegne K, Lei Y, Shen F, Fu H, Sun Y, Xuan Y, Cao J, Cheng Y. Immunogenicity analysis of conserved fragments in Plasmodium ovale species merozoite surface protein 4. Malar J 2020; 19:126. [PMID: 32228600 PMCID: PMC7106901 DOI: 10.1186/s12936-020-03207-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/23/2020] [Indexed: 12/28/2022] Open
Abstract
Background There is an urgent need for an effective vaccine to control and eradicate malaria, one of the most serious global infectious diseases. Plasmodium merozoite surface protein 4 (MSP4) has been listed as a blood-stage subunit vaccine candidate for malaria. Infection with Plasmodium ovale species including P. ovale wallikeri and P. ovale curtisi, is also a source of malaria burden in tropical regions where it is sometimes mixed with other Plasmodium species. However, little is known about P. ovale MSP4. Methods The msp4 gene was amplified through polymerase chain reaction using genomic DNA extracted from blood samples of 46 patients infected with P. ovale spp. and amplified products were sequenced. Open reading frames predicted as immunogenic peptides consisting of 119 and 97 amino acids of P. ovale curtisi MSP4 (PocMSP4) and P. ovale wallikeri MSP4 (PowMSP4), respectively, were selected for protein expression. Recombinant proteins (rPoMSP4) were expressed in Escherichia coli, purified, analysed, and immunized in BALB/c mice. The specificity of anti-MSP4-immunoglobulin (Ig) G antibodies was evaluated by Western blot and enzyme-linked immunosorbent assays, and cellular immune responses were analysed via lymphocyte proliferation assays. Results Full peptide sequences of PocMSP4 and PowMSP4 were completely conserved in all clinical isolates, except in the epidermal growth factor-like domain at the carboxyl terminus where only one mutation was observed in one P. o. wallikeri isolate. Further, truncated PoMSP4 segments were successfully expressed and purified as ~ 32 kDa proteins. Importantly, high antibody responses with end-point titres ranging from 1:10,000 to 1:2,560,000 in all immunized mouse groups were observed, with high IgG avidity to PocMSP4 (80.5%) and PowMSP4 (92.3%). Furthermore, rPocMSP4 and rPowMSP4 cross-reacted with anti-PowMSP4-specific or anti-PocMSP4-specific antibodies. Additionally, anti-PoMSP4 IgG antibodies showed broad immuno-specificity in reacting against rPoMSP1 and rPoAMA1. Lastly, PocMSP4- and PowMSP4-immunized mice induced cellular immune responses with PocMSP4 (36%) and PowMSP4 cells (15.8%) during splenocyte proliferation assays. Conclusion Findings from this study suggest conservation in PoMSP4 protein sequences and high immunogenicity was observed in rPoMSP4. Furthermore, induction of immune responses in PocMSP4- and PowMSP4-immunized mice informed that both humoral and cellular immune responses play crucial roles for PoMSP4 in protection.
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Affiliation(s)
- Juliette Uwase
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Ruilin Chu
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Kokouvi Kassegne
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Yao Lei
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Feihu Shen
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Haitian Fu
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Yifan Sun
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Yinghua Xuan
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Jun Cao
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China. .,Key Laboratory of National Health and Family Planning Commision on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, 214064, Jiangsu, People's Republic of China.
| | - Yang Cheng
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
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Frickmann H, Wegner C, Ruben S, Loderstädt U, Tannich E. A comparison of two PCR protocols for the differentiation of Plasmodium ovale species and implications for clinical management in travellers returning to Germany: a 10-year cross-sectional study. Malar J 2019; 18:272. [PMID: 31399031 PMCID: PMC6688346 DOI: 10.1186/s12936-019-2901-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 08/02/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND To assess the occurrence of Plasmodium ovale wallikeri and Plasmodium ovale curtisi species in travellers returning to Germany, two real-time PCR protocols for the detection and differentiation of the two P. ovale species were compared. Results of parasite differentiation were correlated with patient data. METHODS Residual nucleic acid extractions from EDTA blood samples of patients with P. ovale spp. malaria, collected between 2010 and 2019 at the National Reference Centre for Tropical Pathogens in Germany, were subjected to further parasite discrimination in a retrospective assessment. All samples had been analysed by microscopy and by P. ovale spp.-specific real-time PCR without discrimination on species level. Two different real-time PCR protocols for species discrimination of P. o. curtisi and P. o. wallikeri were carried out. Results were correlated with patient data on gender, age, travel destination, thrombocyte count, and duration of parasite latency. RESULTS Samples from 77 P. ovale spp. malaria patients were assessed, with a male:female ratio of about 2:1 and a median age of 30 years. Parasitaemia was low, ranging from few visible parasites up to 1% infected erythrocytes. Discriminative real-time PCRs revealed 41 cases of P. o. curtisi and 36 cases of P. o. wallikeri infections. Concordance of results by the two PCR approaches was 100%. Assessment of travel destinations confirmed co-existence of P. o. curtisi and P. o. wallikeri over a wide range of countries in sub-Saharan Africa. Latency periods for the two P. ovale species were similar, with median values of 56.0 days for P. o. curtisi and 58.0 days for P. o. wallikeri; likewise, there was no statistically significant difference in thrombocyte count with median values of 138.5/µL for patients with P. o. curtisi and 152.0/µL for P. o. wallikeri-infected patients. CONCLUSIONS Two different real-time PCR protocols were found to be suitable for the discrimination of P. o. curtisi and P. o. wallikeri with only minor differences in sensitivity. Due to the overall low parasitaemia and the lack of differences in severity-related aspects like parasite latency periods or thrombocyte counts, this study supports the use of P. ovale spp. PCR without discrimination on species level to confirm the diagnosis and to inform clinical management of malaria in these patients.
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Affiliation(s)
- Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, External Site at the Bernhard Nocht Institute, Tropical Microbiology and Entomology, Bundeswehr Hospital Hamburg, Bernhard Nocht Str. 74, 20359, Hamburg, Germany. .,Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany.
| | - Christine Wegner
- Bernhard Nocht Institute for Tropical Medicine, National Reference Center for Tropical Pathogens, Hamburg, Germany
| | - Stefanie Ruben
- Bernhard Nocht Institute for Tropical Medicine, National Reference Center for Tropical Pathogens, Hamburg, Germany
| | - Ulrike Loderstädt
- Bernhard Nocht Institute for Tropical Medicine, National Reference Center for Tropical Pathogens, Hamburg, Germany
| | - Egbert Tannich
- Bernhard Nocht Institute for Tropical Medicine, National Reference Center for Tropical Pathogens, Hamburg, Germany
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8
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Zhang X, Chu R, Xu S, Fu H, Tang J, Chen L, Shi X, Chen J, Li Y, Zhu G, Han ET, Xuan Y, Cao J, Cheng Y. Immunogenicity analysis of genetically conserved segments in Plasmodium ovale merozoite surface protein-8. Parasit Vectors 2019; 12:164. [PMID: 30975200 PMCID: PMC6460738 DOI: 10.1186/s13071-019-3412-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 03/26/2019] [Indexed: 12/02/2022] Open
Abstract
Background Plasmodium ovale is widely distributed across tropical regions and has two closely related but distinct species, namely P. ovale curtisi and P. ovale wallikeri. Combining genetic characterization with the immunogenicity of merozoite surface protein-8 (MSP-8) supports considering MSP-8 as a candidate target for blood-stage vaccines against malaria. However, no previous studies have focused on characterizing the genetic diversity and immunogenicity of PoMSP-8. Methods Blood samples were collected from 42 patients infected with P. ovale. The patients were migrant workers returning to the Jiangsu Province from Africa; genomic DNA was extracted from their blood samples for sequencing and protein expression. The recombinant PoMSP-8 (rPoMSP-8) proteins were expressed and purified to assess their immune responses in BALB/c mice. Results The sequences of the P. ovale curtisi and P. ovale wallikeri msp8 genes were completely conserved in each isolate. The rPoMSP-8 proteins were successfully expressed and purified as ~70 kDa proteins. Antibodies raised against rPoMSP-8 in mice showed appropriate immunoreactivity, as evidenced by immunoblotting. These specific antibodies were detected at day 7 post-immunization, and their levels increased throughout the whole immunization period. rPoMSP-8-raised antibodies had high endpoint titers (1:5,120,000) and high avidity (PocMSP-8: 94.84%, PowMSP-8: 92.69%). Cross-reactivity between rPocMSP-8 and rPowMSP-8 was observed with each anti-PoMSP8-specific antibody. Conclusions Remarkable conservation and high immunogenicity was observed in both rPoMSP-8s. Intriguingly, cross-reaction between rPocMSP-8 and rPowMSP-8 was detected, suggesting that a single PoMSP8-based construction might be applicable for both species. Electronic supplementary material The online version of this article (10.1186/s13071-019-3412-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xinxin Zhang
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Ruilin Chu
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Sui Xu
- Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, Jiangsu, People's Republic of China
| | - Haitian Fu
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Jianxia Tang
- Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, Jiangsu, People's Republic of China
| | - Limei Chen
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Xiaodan Shi
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Jing Chen
- Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, Jiangsu, People's Republic of China
| | - Yuhong Li
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China
| | - Guoding Zhu
- Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, Jiangsu, People's Republic of China
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea
| | - Yinghua Xuan
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China.
| | - Jun Cao
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China. .,Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, Jiangsu, People's Republic of China.
| | - Yang Cheng
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, People's Republic of China.
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