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Yadav M, Dahiya N, Janjoter S, Kataria D, Dixit R, Sehrawat N. A review on RNA interference studies in Anophelines to reveal candidate genes for malaria transmission blocking vaccine. Life Sci 2024; 351:122822. [PMID: 38866221 DOI: 10.1016/j.lfs.2024.122822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 05/24/2024] [Accepted: 06/07/2024] [Indexed: 06/14/2024]
Abstract
Malaria is a major public health concern. The development of parasite-based vaccine RTS/AS01 has some therapeutic value but its lower efficacy is one of the major limitations. Mosquito-based transmission-blocking vaccines could have a higher potential for parasite inhibition within the mosquitoes. Several genes of mosquito midgut, salivary gland, hemolymph, etc. get activate in response to the Plasmodium-infected blood and helps in parasite invasion directly or indirectly inside the mosquito. The studies of such genes provided a new insight into developing the more efficient vaccines. In the field of malaria genetics research, RNAi has become an innovative strategy used to identify mosquito candidate genes for transmission-blocking vaccines. This review targeted the gene studies that have been conducted in the period 2000-2023 in different malaria vectors against different malarial parasites using the RNAi approach to reveal mosquito novel gene candidates for vaccine development.
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Affiliation(s)
- Mahima Yadav
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Nisha Dahiya
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Sangeeta Janjoter
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Divya Kataria
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India
| | | | - Neelam Sehrawat
- Department of Genetics, Maharshi Dayanand University, Rohtak, Haryana, India.
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Gao W, Qiu Y, Zhu L, Yu X, Yang F, Chen M, He G, Liu Y, Cui L, Liu F, Zhu X, Cao Y. A dual-antigen malaria vaccine targeting Pb22 and Pbg37 was able to induce robust transmission-blocking activity. Parasit Vectors 2023; 16:455. [PMID: 38098083 PMCID: PMC10720250 DOI: 10.1186/s13071-023-06071-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Despite years of effort to develop an effective vaccine against malaria infection, a vaccine that provides individuals with sufficient protection against malaria illness and death in endemic areas is not yet available. The development of transmission-blocking vaccines (TBVs) is a promising strategy for malaria control. A dual-antigen malaria vaccine targeting both pre- and post-fertilization antigens could effectively improve the transmission-blocking activity of vaccines against the sexual stages of the parasite. METHODS A chimeric recombinant protein Pb22-Pbg37 (Plasmodium berghei 22-P. berghei G37) composed of 19-218 amino acids (aa) of Pb22 and the N-terminal 26-88 aa of Pbg37 was designed and expressed in the Escherichia coli expression system. The antibody titers of the fusion (Pb22-Pbg37) and mixed (Pb22+Pbg37) antigens, as well as those of Pb22 and Pbg37 single antigens were evaluated by enzyme-linked immunosorbent assay. Immunofluorescence and western blot assays were performed to test the reactivity of the antisera with the native proteins in the parasite. The induction of transmission-blocking activity (TBA) by Pb22-Pbg37 and Pb22+Pbg37 were evaluated by in vitro gametocyte activation, gamete and exflagellation center formation, ookinete conversion, and in the direct mosquito feeding assay. RESULTS The Pb22-Pbg37 fusion protein was successfully expressed in vitro. Co-administration of Pb22 and Pbg37 as a fusion or mixed protein elicited comparable antibody responses in mice and resulted in responses to both antigens. Most importantly, both the mixed and fusion antigens induced antibodies with significantly higher levels of TBA than did each of the individual antigens when administered alone. In addition, the efficacy of vaccination with the Pb22-Pbg37 fusion protein was equivalent to that of vaccination with the mixed single antigens. CONCLUSIONS Dual-antigen vaccines, which expand/lengthen the period during which the transmission-blocking antibodies can act during sexual-stage development, can provide a promising higher transmission-reducing activity compared to single antigens.
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Affiliation(s)
- Wenyan Gao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
- Department of Obstetrics, The First Affiliated Hospital of China Medical University, NO. 155, Nanjing Street, Shenyang, 110001, Liaoning, People's Republic of China
| | - Yue Qiu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
- Department of Cardiovascular Ultrasound, The First Hospital of China Medical University, Shenyang, 110001, Liaoning, China
| | - Liying Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Xinxin Yu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Fan Yang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Muyan Chen
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Gang He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Yinjie Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China.
| | - Xiaotong Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No.77 Puhe Road, Shenyang, 110122, Liaoning, People's Republic of China.
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Bai J, Liu F, Yang F, Zhao Y, Jia X, Thongpoon S, Roobsoog W, Sattabongkot J, Zheng L, Cui Z, Zheng W, Cui L, Cao Y. Evaluation of transmission-blocking potential of Pv22 using clinical Plasmodium vivax infections and transgenic Plasmodium berghei. Vaccine 2023; 41:555-563. [PMID: 36503858 PMCID: PMC9812905 DOI: 10.1016/j.vaccine.2022.11.058] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 11/09/2022] [Accepted: 11/23/2022] [Indexed: 12/13/2022]
Abstract
Antigens expressed during the sexual development of malaria parasites are transmission-blocking vaccine (TBV) targets. Pb22, a protein expressed and localized to the plasma membrane of gametes and ookinetes in Plasmodium berghei, is an excellent TBV candidate. Here, we evaluated the TB potential of the Plasmodium vivax ortholog Pv22 using a transgenic P. berghei parasite line and P. vivax clinical isolates. The full-length recombinant Pv22 (rPv22) protein was produced and used to immunize mice and rabbits to obtain antibodies. We generated a transgenic P. berghei line (TrPv22Pb) by inserting the pv22 gene into the pb22 locus and showed that Pv22 expression completely rescued the defects in male gametogenesis of the pb22 deletion parasite. Since Pv22 in the transgenic parasite showed similar expression and localization patterns to Pb22, we used the TrPv22Pb parasite as a surrogate to evaluate the TB potential of Pv22. In mosquito feeding assays, mosquitoes feeding on rPv22-immunized mice infected with TrPv22Pb parasites showed a 49.3-53.3 % reduction in the oocyst density compared to the control group. In vitro assays showed that the rPv22 immune sera significantly inhibited exflagellation and ookinete formation of the TrPv22Pb parasites. In a direct membrane feeding assay using three clinical P. vivax isolates, the rabbit anti-rPv22 antibodies also significantly decreased the oocyst density by 53.7, 30.2, and 26.2 %, respectively. This study demonstrated the feasibility of using transgenic P. berghei parasites expressing P. vivax antigens as a potential tool to evaluate TBV candidates. However, the much weaker TB activity of Pv22 obtained from two complementary assays suggest that Pv22 may not be a promising TBV candidate for P. vivax.
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Affiliation(s)
- Jie Bai
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Fan Yang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Xitong Jia
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Sataporn Thongpoon
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Wanlapa Roobsoog
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Thailand
| | - Li Zheng
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Zeshi Cui
- College of Pharmacy, China Medical University, Shenyang, China
| | - Wenqi Zheng
- Department of Clinical Laboratory, Affiliated Hospital of Inner Mongolian Medical University, Hohhot, China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States.
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China.
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Wang PP, Jiang X, Zhu L, Zhou D, Hong M, He L, Chen L, Yao S, Zhao Y, Chen G, Wang C, Cui L, Cao Y, Zhu X. A G-Protein-Coupled Receptor Modulates Gametogenesis via PKG-Mediated Signaling Cascade in Plasmodium berghei. Microbiol Spectr 2022; 10:e0015022. [PMID: 35404079 PMCID: PMC9045217 DOI: 10.1128/spectrum.00150-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 03/20/2022] [Indexed: 12/13/2022] Open
Abstract
Gametogenesis is essential for malaria parasite transmission, but the molecular mechanism of this process remains to be refined. Here, we identified a G-protein-coupled receptor 180 (GPR180) that plays a critical role in signal transduction during gametogenesis in Plasmodium. The P. berghei GPR180 was predominantly expressed in gametocytes and ookinetes and associated with the plasma membrane in female gametes and ookinetes. Knockout of pbgpr180 (Δpbgpr180) had no noticeable effect on blood-stage development but impaired gamete formation and reduced transmission of the parasites to mosquitoes. Transcriptome analysis revealed that a large proportion of the dysregulated genes in the Δpbgpr180 gametocytes had assigned functions in cyclic nucleotide signal transduction. In the Δpbgpr180 gametocytes, the intracellular cGMP level was significantly reduced, and the cytosolic Ca2+ mobilization showed a delay and a reduction in the magnitude during gametocyte activation. These results suggest that PbGPR180 functions upstream of the cGMP-protein kinase G-Ca2+ signaling pathway. In line with this functional prediction, the PbGPR180 protein was found to interact with several transmembrane transporter proteins and the small GTPase Rab6 in activated gametocytes. Allele replacement of pbgpr180 with the P. vivax ortholog pvgpr180 showed equal competence of the transgenic parasite in sexual development, suggesting functional conservation of this gene in Plasmodium spp. Furthermore, an anti-PbGPR180 monoclonal antibody and the anti-PvGPR180 serum possessed robust transmission-blocking activities. These results indicate that GPR180 is involved in signal transduction during gametogenesis in malaria parasites and is a promising target for blocking parasite transmission. IMPORTANCE Environmental changes from humans to mosquitoes activate gametogenesis of the malaria parasite, an obligative process for parasite transmission, but how the signals are relayed remains poorly understood. Here, we show the identification of a Plasmodium G-protein-coupled receptor, GPR180, and the characterization of its function in gametogenesis. In P. berghei, GPR180 is dispensable for asexual development and gametocytogenesis, but its deletion impairs gametogenesis and reduces transmission to mosquitoes. GPR180 appears to function upstream of the cGMP-protein kinase G-Ca2+ signaling pathway and is required for the maximum activity of this pathway. Genetic complementation shows that the GPR180 ortholog from the human malaria parasite P. vivax was fully functional in P. berghei, indicating functional conservation of GPR180 in Plasmodium spp. With predominant expression and membrane association of GPR180 in sexual stages, GPR180 is a promising target for blocking transmission, and antibodies against GPR180 possess robust transmission-blocking activities.
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Affiliation(s)
- Peng-peng Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
- Department of Laboratory Medicine, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xuefeng Jiang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Liying Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Dan Zhou
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Mingyang Hong
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Lu He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Lumeng Chen
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Shijie Yao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Guang Chen
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
- Department of Basic Medical Sciences, Taizhou University Hospital, Taizhou University, Taizhou, China
| | - Chengqi Wang
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Xiaotong Zhu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
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Kumari V, Prasad KM, Kalia I, Sindhu G, Dixit R, Rawat DS, Singh OP, Singh AP, Pandey KC. Dissecting The role of Plasmodium metacaspase-2 in malaria gametogenesis and sporogony. Emerg Microbes Infect 2022; 11:938-955. [PMID: 35264080 PMCID: PMC8973346 DOI: 10.1080/22221751.2022.2052357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The family of apicomplexan specific proteins contains caspases–like proteins called “metacaspases”. These enzymes are present in the malaria parasite but absent in human; therefore, these can be explored as potential drug targets. We deleted the MCA-2 gene from Plasmodium berghei genome using a gene knockout strategy to decipher its precise function. This study has identified that MCA-2 plays an important role in parasite transmission since it is critical for the formation of gametocytes and for maintaining an appropriate number of infectious sporozoites required for sporogony. It is noticeable that a significant reduction in gametocyte, oocysts, ookinete and sporozoites load along with a delay in hepatocytes invasion were observed in the MCA-2 knockout parasite. Furthermore, a study found the two MCA-2 inhibitory molecules known as C-532 and C-533, which remarkably inhibited the MCA-2 activity, abolished the in vitro parasite growth, and also impaired the transmission cycle of P. falciparum and P. berghei in An. stephensi. Our findings indicate that the deletion of MCA-2 hampers the Plasmodium development during erythrocytic and exo-erythrocytic stages, and its inhibition by C-532 and C-533 critically affects the malaria transmission biology.
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Affiliation(s)
- Vandana Kumari
- ICMR-National Institute of Malaria Research, New Delhi, India
| | | | | | | | - Rajnikant Dixit
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Diwan S Rawat
- Depatment of Chemistry, University of Delhi, New Delhi, India
| | - O P Singh
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Agam P Singh
- National Institute of Immunology, New Delhi, India
| | - Kailash C Pandey
- ICMR-National Institute of Malaria Research, New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad Uttar Pradesh, UP, India
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Yu S, Wang J, Luo X, Zheng H, Wang L, Yang X, Wang Y. Transmission-Blocking Strategies Against Malaria Parasites During Their Mosquito Stages. Front Cell Infect Microbiol 2022; 12:820650. [PMID: 35252033 PMCID: PMC8889032 DOI: 10.3389/fcimb.2022.820650] [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: 11/23/2021] [Accepted: 01/31/2022] [Indexed: 11/24/2022] Open
Abstract
Malaria is still the most widespread parasitic disease and causes the most infections globally. Owing to improvements in sanitary conditions and various intervention measures, including the use of antimalarial drugs, the malaria epidemic in many regions of the world has improved significantly in the past 10 years. However, people living in certain underdeveloped areas are still under threat. Even in some well-controlled areas, the decline in malaria infection rates has stagnated or the rates have rebounded because of the emergence and spread of drug-resistant malaria parasites. Thus, new malaria control methods must be developed. As the spread of the Plasmodium parasite is dependent on the part of its life cycle that occurs in mosquitoes, to eliminate the possibility of malaria infections, transmission-blocking strategies against the mosquito stage should be the first choice. In fact, after the gametocyte enters the mosquito body, it undergoes a series of transformation processes over a short period, thus providing numerous potential blocking targets. Many research groups have carried out studies based on targeting the blocking of transmission during the mosquito phase and have achieved excellent results. Meanwhile, the direct killing of mosquitoes could also significantly reduce the probability of malaria infections. Microorganisms that display complex interactions with Plasmodium, such as Wolbachia and gut flora, have shown observable transmission-blocking potential. These could be used as a biological control strategy and play an important part in blocking the transmission of malaria.
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Affiliation(s)
- Shasha Yu
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
| | - Jing Wang
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
| | - Xue Luo
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
| | - Hong Zheng
- Department of Thoracic Surgery, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Luhan Wang
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
| | - Xuesen Yang
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
| | - Ying Wang
- Department of Tropical Medicine, College of Military Preventive Medicine, Army Medical University, Chongqing, China
- *Correspondence: Ying Wang,
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Takashima E, Tachibana M, Morita M, Nagaoka H, Kanoi BN, Tsuboi T. Identification of Novel Malaria Transmission-Blocking Vaccine Candidates. Front Cell Infect Microbiol 2021; 11:805482. [PMID: 34917521 PMCID: PMC8670312 DOI: 10.3389/fcimb.2021.805482] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 11/16/2021] [Indexed: 01/02/2023] Open
Abstract
Control measures have significantly reduced malaria morbidity and mortality in the last two decades; however, the downward trends have stalled and have become complicated by the emergence of COVID-19. Significant efforts have been made to develop malaria vaccines, but currently only the RTS,S/AS01 vaccine against Plasmodium falciparum has been recommended by the WHO, for widespread use among children in sub-Saharan Africa. The efficacy of RTS,S/AS01 is modest, and therefore the development of more efficacious vaccines is still needed. In addition, the development of transmission-blocking vaccines (TBVs) to reduce the parasite transmission from humans to mosquitoes is required toward the goal of malaria elimination. Few TBVs have reached clinical development, and challenges include low immunogenicity or high reactogenicity in humans. Therefore, novel approaches to accelerate TBV research and development are urgently needed, especially novel TBV candidate discovery. In this mini review we summarize the progress in TBV research and development, novel TBV candidate discovery, and discuss how to accelerate novel TBV candidate discovery.
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Affiliation(s)
- Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Mayumi Tachibana
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Japan
| | - Masayuki Morita
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Bernard N Kanoi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Takafumi Tsuboi
- Division of Cell-Free Sciences, Proteo-Science Center, Ehime University, Matsuyama, Japan
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Zhang Y, Liu F, Zhao Y, Yang F, Bai J, Jia X, Roobsoong W, Sattabongkot J, Cui L, Cao Y, Luo E, Wang M. Evaluation of two Plasmodium vivax sexual stage antigens as transmission-blocking vaccine candidates. Parasit Vectors 2021; 14:407. [PMID: 34399829 PMCID: PMC8366161 DOI: 10.1186/s13071-021-04909-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 07/30/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium vivax transmission-blocking vaccines (TBVs) are receiving increasing attention. Based on excellent transmission-blocking activities of the PbPH (PBANKA_0417200) and PbSOP26 (PBANKA_1457700) antigens in Plasmodium berghei, their orthologs in P. vivax, PVX_098655 (PvPH) and PVX_101120 (PvSOP26), were selected for the evaluation of their potential as TBVs. METHODS Fragments of PvPH (amino acids 22-304) and PvSOP26 (amino acids 30-272) were expressed in the yeast expression system. The recombinant proteins were used to immunize mice to obtain antisera. The transmission-reducing activities of these antisera were evaluated using the direct membrane feeding assay (DMFA) using Anopheles dirus mosquitoes and P. vivax clinical isolates. RESULTS The recombinant proteins PvPH and PvSOP26 induced robust antibody responses in mice. The DMFA showed that the anti-PvSOP26 sera significantly reduced oocyst densities by 92.0 and 84.1% in two parasite isolates, respectively, whereas the anti-PvPH sera did not show evident transmission-reducing activity. The variation in the DMFA results was unlikely due to the genetic polymorphisms of the two genes since their respective sequences were identical in the clinical P. vivax isolates. CONCLUSION PvSOP26 could be a promising TBV candidate for P. vivax, which warrants further evaluation.
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Affiliation(s)
- Yongzhe Zhang
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
- Department of Nephrology, Shengjing Hospital of China Medical University, Shenyang, 110004, Liaoning, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Fan Yang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Jie Bai
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Xitong Jia
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Wanlapa Roobsoong
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Suite 304, Tampa, FL, 33612-9415, USA
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China
| | - Enjie Luo
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China.
| | - Meilian Wang
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, 110122, Liaoning, China.
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Liu F, Yang F, Wang Y, Hong M, Zheng W, Min H, Li D, Jin Y, Tsuboi T, Cui L, Cao Y. A conserved malaria parasite antigen Pb22 plays a critical role in male gametogenesis in Plasmodium berghei. Cell Microbiol 2020; 23:e13294. [PMID: 33222390 DOI: 10.1111/cmi.13294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 10/28/2020] [Accepted: 11/16/2020] [Indexed: 12/13/2022]
Abstract
Gametogenesis, the formation of gametes from gametocytes, an essential step for malaria parasite transmission, is targeted by transmission-blocking drugs and vaccines. We identified a conserved protein (PBANKA_0305900) in Plasmodium berghei, which encodes a protein of 22 kDa (thus named Pb22) and is expressed in both asexual stages and gametocytes. Its homologues are present in all Plasmodium species and its closely related, Hepatocystis, but not in other apicomplexans. Pb22 protein was localised in the cytosols of schizonts, as well as male and female gametocytes. During gamete-to-ookinete development, Pb22 became localised on the plasma membranes of gametes and ookinetes. Compared to the wild-type (WT) parasites, P. berghei with pb22 knockout (KO) showed a significant reduction in exflagellation (~89%) of male gametocytes and ookinete number (~97%) during in vitro ookinete culture. Mosquito feeding assays showed that ookinete and oocyst formation of the pb22-KO line in mosquito midguts was almost completely abolished. These defects were rescued in parasites where pb22 was restored. Cross-fertilisation experiments with parasite lines defective in either male or female gametes confirmed that the defects in the pb22-KO line were restricted to the male gametes, whereas female gametes in the pb22-KO line were fertile at the WT level. Detailed analysis of male gametogenesis showed that 30% of the male gametocytes in the pb22-KO line failed to assemble the axonemes, whereas ~48.9% of the male gametocytes formed flagella but failed to egress from the host erythrocyte. To explore its transmission-blocking potential, recombinant Pb22 (rPb22) was expressed and used to immunise mice. in vitro assays showed that the rPb22-antisera significantly inhibited exflagellation by ~64.8% and ookinete formation by ~93.4%. Mosquitoes after feeding on rPb22-immunised mice also showed significant decreases in infection prevalence (83.3-93.3%) and oocyst density (93.5-99.6%). Further studies of the Pb22 orthologues in human malaria parasites are warranted.
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Affiliation(s)
- Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Fan Yang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yaru Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Minsheng Hong
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Wenqi Zheng
- Department of Clinical Laboratory, Affiliated Hospital of Inner Mongolian Medical University, Hohhot, China
| | - Hui Min
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China.,Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Danni Li
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Ying Jin
- Division of Administration, Liaoning Research Institute of Family Planning, Shenyang, China
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
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10
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Tremp AZ, Saeed S, Sharma V, Lasonder E, Dessens JT. Plasmodium berghei LAPs form an extended protein complex that facilitates crystalloid targeting and biogenesis. J Proteomics 2020; 227:103925. [PMID: 32736136 PMCID: PMC7487766 DOI: 10.1016/j.jprot.2020.103925] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 06/21/2020] [Accepted: 07/24/2020] [Indexed: 12/26/2022]
Abstract
Passage of malaria parasites through mosquitoes involves multiple developmental transitions, from gametocytes that are ingested with the blood meal, through to sporozoites that are transmitted by insect bite to the host. During the transformation from gametocyte to oocyst, the parasite forms a unique transient organelle named the crystalloid, which is involved in sporozoite formation. In Plasmodium berghei, a complex of six LCCL domain-containing proteins (LAPs) reside in the crystalloid and are required for its biogenesis. However, little else is known about the molecular mechanisms that underlie the crystalloid's role in sporogony. In this study, we have used transgenic parasites stably expressing LAP3 fused to GFP, combined with GFP affinity pulldown and high accuracy mass spectrometry, to identify an extended LAP interactome of some fifty proteins. We show that many of these are targeted to the crystalloid, including members of two protein families with CPW-WPC and pleckstrin homology-like domains, respectively. Our findings indicate that the LAPs are part of an intricate protein complex, the formation of which facilitates both crystalloid targeting and biogenesis. Significance Reducing malaria parasite transmission by mosquitoes is a key component of malaria eradication and control strategies. This study sheds important new light on the molecular composition of the crystalloid, an enigmatic parasite organelle that is essential for sporozoite formation and transmission from the insect to the vertebrate host. Our findings provide new mechanistic insight into how proteins are delivered to the crystalloid, and indicate that the molecular mechanisms that underlie crystalloid function are complex, involving several protein families unique to Plasmodium and closely related organisms. The new crystalloid proteins identified will form a useful starting point for studies aimed at unravelling how the crystalloid organelle facilitates sporogony and transmission. A Plasmodium berghei LAP3 interactome of some 50 proteins was determined. Many proteins in the interactome constitute known or novel crystalloid proteins. The interactome includes protein families with PH-like and CPW-WPC domains.
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Affiliation(s)
- Annie Z Tremp
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Sadia Saeed
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Vikram Sharma
- School of Biomedical Sciences, Faculty of Health, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK
| | - Edwin Lasonder
- School of Biomedical Sciences, Faculty of Health, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK; Department of Applied Sciences, Faculty of Life and Health Sciences, Northumbria University, Newcastle-Upon-Tyne, NE1 8ST, UK
| | - Johannes T Dessens
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
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11
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Miura K, Tachibana M, Takashima E, Morita M, Kanoi BN, Nagaoka H, Baba M, Torii M, Ishino T, Tsuboi T. Malaria transmission-blocking vaccines: wheat germ cell-free technology can accelerate vaccine development. Expert Rev Vaccines 2019; 18:1017-1027. [PMID: 31566026 PMCID: PMC11000147 DOI: 10.1080/14760584.2019.1674145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 09/25/2019] [Indexed: 12/18/2022]
Abstract
Introduction: Highly effective malaria vaccines are essential component toward malaria elimination. Although the leading malaria vaccine, RTS,S/AS01, with modest efficacy is being evaluated in a pilot feasibility trial, development of a malaria transmission-blocking vaccine (TBV) could make a major contribution toward malaria elimination. Only a few TBV antigens have reached pre-clinical or clinical development but with several challenges including difficulties in the expression of malaria recombinant proteins and low immunogenicity in humans. Therefore, novel approaches to accelerate TBV research to preclinical development are critical to generate an efficacious TBV.Areas covered: PubMed was searched to review the progress and future prospects of malaria TBV research and development. We also reviewed registered trials at ClinicalTrials.gov as well as post-genome TBV candidate discovery research including our efforts.Expert opinion: Wheat germ cell-free protein synthesis technology can accelerate TBV development by overcoming some current challenges of TBV research.
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Affiliation(s)
- Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Mayumi Tachibana
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Masayuki Morita
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Bernard N Kanoi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Minami Baba
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Japan
| | - Motomi Torii
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Japan
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Tomoko Ishino
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Japan
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
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12
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Liu F, Liu Q, Yu C, Zhao Y, Wu Y, Min H, Qiu Y, Jin Y, Miao J, Cui L, Cao Y. An MFS-Domain Protein Pb115 Plays a Critical Role in Gamete Fertilization of the Malaria Parasite Plasmodium berghei. Front Microbiol 2019; 10:2193. [PMID: 31616399 PMCID: PMC6764285 DOI: 10.3389/fmicb.2019.02193] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 09/06/2019] [Indexed: 12/20/2022] Open
Abstract
Sexual reproduction is an essential process in the Plasmodium life cycle and a vulnerable step for blocking transmission from the human host to mosquitoes. In this study, we characterized the functions of a conserved cell membrane protein P115 in the rodent malaria parasite Plasmodium berghei ANKA. Pb115 was expressed in both asexual stages (schizonts) and sexual stages (gametocytes, gametes, and ookinetes), and was localized on the plasma membrane of gametes and ookinetes. In P. berghei, genetic deletion of Pb115 (Δpb115) did not affect asexual multiplication, nor did it affect gametocyte development or exflagellation of the male gametocytes. However, mosquitoes fed on Δpb115-infected mice showed 74% reduction in the prevalence of infection and 96.5% reduction in oocyst density compared to those fed on wild-type P. berghei-infected mice. The Δpb115 parasites showed significant defects in the interactions between the male and female gametes, and as a result, very few zygotes were formed in ookinete cultures. Cross fertilization with the male-defective Δpbs48/45 line and the female-defective Δpfs47 line further indicated that the fertilization defects of the Δpb115 lines were present in both male and female gametes. We evaluated the transmission-blocking potential of Pb115 by immunization of mice with a recombinant Pb115 fragment. In vivo mosquito feeding assay showed Pb115 immunization conferred modest, but significant transmission reducing activity with 44% reduction in infection prevalence and 39% reduction in oocyst density. Our results described functional characterization of a conserved membrane protein as a fertility factor in Plasmodium and demonstrated transmission-blocking potential of this antigen.
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Affiliation(s)
- Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Qingyang Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Chunyun Yu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yan Zhao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yudi Wu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Hui Min
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Tampa, FL, United States
| | - Yue Qiu
- The First Hospital of China Medical University, Shenyang, China
| | - Ying Jin
- Liaoning Research Institute of Family Planning, Shenyang, China
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Tampa, FL, United States
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Tampa, FL, United States
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, China
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13
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Zhu X, Sun L, He Y, Wei H, Hong M, Liu F, Liu Q, Cao Y, Cui L. Plasmodium berghei serine/threonine protein phosphatase PP5 plays a critical role in male gamete fertility. Int J Parasitol 2019; 49:685-695. [DOI: 10.1016/j.ijpara.2019.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 03/18/2019] [Indexed: 02/06/2023]
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14
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Jenwithisuk R, Kangwanrangsan N, Tachibana M, Thongkukiatkul A, Otsuki H, Sattabongkot J, Tsuboi T, Torii M, Ishino T. Identification of a PH domain-containing protein which is localized to crystalloid bodies of Plasmodium ookinetes. Malar J 2018; 17:466. [PMID: 30545367 PMCID: PMC6291999 DOI: 10.1186/s12936-018-2617-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 12/06/2018] [Indexed: 11/30/2022] Open
Abstract
Background For the success of the malaria control and eradication programme it is essential to reduce parasite transmission by mosquito vectors. In the midguts of mosquitoes fed with parasite-infected blood, sexual-stage parasites fertilize to develop into motile ookinetes that traverse midgut epithelial cells and reside adjacent the basal lamina. Therefore, the ookinete is a promising target of transmission-blocking vaccines to break the parasite lifecycle in mosquito vectors. However, the molecular mechanisms of ookinete formation and invasion of epithelial cells have not been fully elucidated. A unique structure called the crystalloid body has been identified in the ookinete cytoplasm by electron microscopy, but its biological functions remain unclear. Methods A recombinant protein of a novel molecule, designated as crystalloid body specific PH domain-containing protein of Plasmodium yoelii (PyCryPH), was synthesized using a wheat germ cell-free system. Specific rabbit antibodies against PyCryPH were obtained to characterize the expression and localization of PyCryPH during sexual-stage parasite development. In addition, PyCryPH knockout parasites were generated by targeted gene disruption to examine PyCryPH function in mosquito-stage parasite development. Results Western blot and immunofluorescence assays using specific antibodies showed that PyCryPH is specifically expressed in zygotes and ookinetes. By immunoelectron microscopy it was demonstrated that PyCryPH is localized within crystalloid bodies. Parasites with a disrupted PyCryPH gene developed normally into ookinetes and formed oocysts on the basal lamina of midguts. In addition, the number of sporozoites residing in salivary glands was comparable to that of wild-type parasites. Conclusions CryPH, containing a signal peptide and PH domain, is predominantly expressed in zygotes and ookinetes and is localized to crystalloid bodies in P. yoelii. CryPH accumulates in vesicle-like structures prior to the appearance of typical crystalloid bodies. Unlike other known crystalloid body localized proteins, CryPH does not appear to have a multiple domain architecture characteristic of the LAP/CCp family proteins. Although CryPH is highly conserved among Plasmodium, Babesia, Theileria, and Cryptosporidium, PyCryPH is dispensable for the development of invasive ookinetes and sporozoites in mosquito bodies. Electronic supplementary material The online version of this article (10.1186/s12936-018-2617-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rachaneeporn Jenwithisuk
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, 791-0295, Japan.,Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Niwat Kangwanrangsan
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Mayumi Tachibana
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, 791-0295, Japan
| | - Amporn Thongkukiatkul
- Department of Biology, Faculty of Science, Burapha University, Chonburi, 20131, Thailand
| | - Hitoshi Otsuki
- Division of Medical Zoology, Faculty of Medicine, Tottori University, Yonago, Tottori, 683-8503, Japan
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan
| | - Motomi Torii
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, 791-0295, Japan
| | - Tomoko Ishino
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, 791-0295, Japan.
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15
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Antimalarial Transmission-Blocking Interventions: Past, Present, and Future. Trends Parasitol 2018; 34:735-746. [PMID: 30082147 DOI: 10.1016/j.pt.2018.07.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/14/2018] [Accepted: 07/02/2018] [Indexed: 12/17/2022]
Abstract
Malaria remains a major global health challenge. Appropriate use of current antimalarial tools has reduced the disease burden, but morbidity and mortality remain unacceptably high. It is widely accepted that, to achieve long-term control/eradication, it will be necessary to use interventions that inhibit the transmission of parasites to mosquitoes - these tools are termed transmission-blocking interventions (TBIs). This article aims to outline the rationale for the development of TBIs, with a focus on transmission-blocking drugs and (parasite-derived) transmission-blocking vaccines. We describe and summarise the current status of each of these intervention classes and attempt to identify future requirements in development, with a focus on the challenges of establishing each method within an integrated malarial control programme in the future.
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16
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Kou X, Zheng W, Du F, Liu F, Wang M, Fan Q, Cui L, Luo E, Cao Y. Erratum to: Characterization of a Plasmodium berghei sexual stage antigen PbPH as a new candidate for malaria transmission-blocking vaccine. Parasit Vectors 2017; 10:84. [PMID: 28209188 PMCID: PMC5311730 DOI: 10.1186/s13071-017-2021-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 02/06/2017] [Indexed: 12/02/2022] Open
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17
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Wang J, Zheng W, Liu F, Wang Y, He Y, Zheng L, Fan Q, Luo E, Cao Y, Cui L. Characterization of Pb51 in Plasmodium berghei as a malaria vaccine candidate targeting both asexual erythrocytic proliferation and transmission. Malar J 2017; 16:458. [PMID: 29132428 PMCID: PMC5683326 DOI: 10.1186/s12936-017-2107-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 11/02/2017] [Indexed: 11/10/2022] Open
Abstract
Background A vaccine that targets multiple developmental stages of malaria parasites would be an effective tool for malaria control and elimination. Methods A conserved gene in Plasmodium, the Plasmodium berghei gene (PBANKA_020570) encoding a 51 kDa protein (pb51 gene), was identified through search of the PlasmoDB database using a combination of expression and protein localization criteria. A partial domain of the Pb51 protein was expressed in a prokaryotic expression system (rPb51) and used for immunization in mice. The protein expression profile and localization were studied by Western blot and indirect immunofluorescence assay (IFA), respectively. The inhibitory effect of the anti-rPb51 antibodies on parasite proliferation was evaluated in erythrocytes in vivo. The transmission-blocking activity of the immune sera was determined by in vitro ookinete conversion assay and by direct mosquito feeding assay (DFA). Results The rPb51 elicited specific antibodies in mice. Western blot confirmed Pb51 expression in schizonts, gametocytes and ookinetes. IFA showed localization of Pb51 on the outer membranes of schizonts, gametocytes, zygotes, retorts, ookinetes and sporozoites of P. berghei. Mice immunized with the rPb51 protein significantly reduced parasite proliferation and gametocyte conversion in vivo. Moreover, the rPb51 antisera also significantly reduced the in vitro ookinete conversion when added into the ookinete culture medium. In DFA, mice immunized with the rPb51 reduced the prevalence of mosquito infection by 21.3% and oocyst density by 54.8%. Conclusions In P. berghei, P51 was expressed in both asexual erythrocytic and sexual stages and localized on the surface of these stages with the exception of the ring stage. The anti-rPb51 antibodies inhibited both P. berghei proliferation in mice and transmission of the parasite to mosquitoes. Electronic supplementary material The online version of this article (10.1186/s12936-017-2107-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jian Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Wenqi Zheng
- Laboratory of Surgery, The Affiliated Hospital, Inner Mongolia Medical University, Hohhot, 010050, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Yaru Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Yiwen He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Li Zheng
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Enjie Luo
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China.
| | - Liwang Cui
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China.,Department of Entomology, Pennsylvania State University, University Park, PA, 16802, USA
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18
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Zheng W, Liu F, He Y, Liu Q, Humphreys GB, Tsuboi T, Fan Q, Luo E, Cao Y, Cui L. Functional characterization of Plasmodium berghei PSOP25 during ookinete development and as a malaria transmission-blocking vaccine candidate. Parasit Vectors 2017; 10:8. [PMID: 28057055 PMCID: PMC5217559 DOI: 10.1186/s13071-016-1932-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 12/06/2016] [Indexed: 12/23/2022] Open
Abstract
Background Plasmodium ookinete surface proteins as post-fertilization target antigens are potential malaria transmission-blocking vaccine (TBV) candidates. Putative secreted ookinete protein 25 (PSOP25) is a highly conserved ookinete surface protein, and has been shown to be a promising novel TBV target. Here, we further investigated the TBV activities of the full-length recombinant PSOP25 (rPSOP25) protein in Plasmodium berghei, and characterized the potential functions of PSOP25 during the P. berghei life-cycle. Methods We expressed the full-length P. berghei PSOP25 protein in a prokaryotic expression system, and developed polyclonal mouse antisera and a monoclonal antibody (mAb) against the recombinant protein. Indirect immunofluorescence assay (IFA) and Western blot were used to test the specificity of antibodies. The transmission-blocking (TB) activities of antibodies were evaluated by the in vitro ookinete conversion assay and by direct mosquito feeding assay (DFA). Finally, the function of PSOP25 during Plasmodium development was studied by deleting the psop25 gene. Results Both polyclonal mouse antisera and anti-rPSOP25 mAb recognized the PSOP25 proteins in the parasites, and IFA showed the preferential expression of PSOP25 on the surface of zygotes, retorts and mature ookinetes. In vitro, these antibodies significantly inhibited ookinetes formation in an antibody concentration-dependent manner. In DFA, mice immunized with the rPSOP25 and those receiving passive transfer of the anti-rPSOP25 mAb reduced the prevalence of mosquito infection by 31.2 and 26.1%, and oocyst density by 66.3 and 63.3%, respectively. Genetic knockout of the psop25 gene did not have a detectable impact on the asexual growth of P. berghei, but significantly affected the maturation of ookinetes and the formation of midgut oocysts. Conclusions The full-length rPSOP25 could elicit strong antibody response in mice. Polyclonal and monoclonal antibodies against PSOP25 could effectively block the formation of ookinetes in vitro and transmission of the parasites to mosquitoes. Genetic manipulation study indicated that PSOP25 is required for ookinete maturation in P. berghei. These results support further testing of the PSOP25 orthologs in human malaria parasites as promising TBV candidates. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1932-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wenqi Zheng
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China.,Laboratory of Surgery, The Affiliated Hospital, Inner Mongolia Medical University, Hohhot, 010050, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Yiwen He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Qingyang Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Gregory B Humphreys
- Department of Entomology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Takafumi Tsuboi
- Cell-free Science and Technology Research Center, Ehime University, Matsuyama, Ehime, 790-8577, Japan
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Enjie Luo
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, 110001, China.
| | - Liwang Cui
- Department of Entomology, The Pennsylvania State University, University Park, PA, 16802, USA
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