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Evolution of tetraspanin antigens in the zoonotic Asian blood fluke Schistosoma japonicum. Parasit Vectors 2023; 16:97. [PMID: 36918965 PMCID: PMC10012309 DOI: 10.1186/s13071-023-05706-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 02/17/2023] [Indexed: 03/16/2023] Open
Abstract
BACKGROUND Despite successful control efforts in China over the past 60 years, zoonotic schistosomiasis caused by Schistosoma japonicum remains a threat with transmission ongoing and the risk of localised resurgences prompting calls for a novel integrated control strategy, with an anti-schistosome vaccine as a core element. Anti-schistosome vaccine development and immunisation attempts in non-human mammalian host species, intended to interrupt transmission, and utilising various antigen targets, have yielded mixed success, with some studies highlighting variation in schistosome antigen coding genes (ACGs) as possible confounders of vaccine efficacy. Thus, robust selection of target ACGs, including assessment of their genetic diversity and antigenic variability, is paramount. Tetraspanins (TSPs), a family of tegument-surface antigens in schistosomes, interact directly with the host's immune system and are promising vaccine candidates. Here, for the first time to our knowledge, diversity in S. japonicum TSPs (SjTSPs) and the impact of diversifying selection and sequence variation on immunogenicity in these protiens were evaluated. METHODS SjTSP sequences, representing parasite populations from seven provinces across China, were gathered by baiting published short-read NGS data and were analysed using in silico methods to measure sequence variation and selection pressures and predict the impact of selection on variation in antigen protein structure, function and antigenic propensity. RESULTS Here, 27 SjTSPs were identified across three subfamilies, highlighting the diversity of TSPs in S. japonicum. Considerable variation was demonstrated for several SjTSPs between geographical regions/provinces, revealing that episodic, diversifying positive selection pressures promote amino acid variation/variability in the large extracellular loop (LEL) domain of certain SjTSPs. Accumulating polymorphisms in the LEL domain of SjTSP-2, -8 and -23 led to altered structural, functional and antibody binding characteristics, which are predicted to impact antibody recognition and possibly blunt the host's ability to respond to infection. Such changes, therefore, appear to represent a mechanism utilised by S. japonicum to evade the host's immune system. CONCLUSION Whilst the genetic and antigenic geographic variability observed amongst certain SjTSPs could present challenges to vaccine development, here we demonstrate conservation amongst SjTSP-1, -13 and -14, revealing their likely improved utility as efficacious vaccine candidates. Importantly, our data highlight that robust evaluation of vaccine target variability in natural parasite populations should be a prerequisite for anti-schistosome vaccine development.
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Evaluation of Immunogenicity and Efficacy of Fasciola hepatica Tetraspanin 2 (TSP2) Fused to E. coli Heat-Labile Enterotoxin B Subunit LTB Adjuvant Following Intranasal Vaccination of Cattle. Vaccines (Basel) 2021; 9:vaccines9111213. [PMID: 34835144 PMCID: PMC8623123 DOI: 10.3390/vaccines9111213] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/15/2021] [Accepted: 10/16/2021] [Indexed: 11/16/2022] Open
Abstract
Fasciolosis, caused by the liver flukes Fasciola hepatica and F. gigantica, is an economically important and globally distributed zoonotic disease. Liver fluke infections in livestock cause significant losses in production and are of particular concern to regions where drug resistance is emerging. Antigens of the F. hepatica surface tegument represent promising vaccine candidates for controlling this disease. Tetraspanins are integral tegumental antigens that have shown partial protection as vaccine candidates against other trematode species. The Escherichia coli heat-labile enterotoxin's B subunit (LTB) is a potent mucosal adjuvant capable of inducing an immune response to fused antigens. This study investigates the potential of F. hepatica tetraspanin 2 extracellular loop 2 (rFhTSP2) as a protective vaccine antigen and determines if fusion of FhTSP2 to LTB can enhance protection in cattle. Cattle were immunised subcutaneously with rFhTSP2 mixed in the Freund's adjuvant and intranasally with rLTB-FhTSP2 in saline, accounting for equal molar ratios of tetraspanin in both groups. Vaccination with rFhTSP2 stimulated a strong specific serum IgG response, whereas there was no significant serum IgG response following rLTB-FhTSP2 intranasal vaccination. There was no substantial antigen specific serum IgA generated in all groups across the trial. Contrastingly, after the fluke challenge, a rise in antigen specific saliva IgA was observed in both vaccination groups on Day 42, with the rLTB-FhTSP2 vaccination group showing significant mucosal IgA production at Day 84. However, neither vaccine group showed a significant reduction of fluke burden nor faecal egg output. These results suggest that intranasal vaccination with rLTB-FhTSP2 does elicit a humoral mucosal response but further work is needed to evaluate if mucosal delivery of liver fluke antigens fused to LTB is a viable vaccine strategy.
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Panzner U, Excler JL, Kim JH, Marks F, Carter D, Siddiqui AA. Recent Advances and Methodological Considerations on Vaccine Candidates for Human Schistosomiasis. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.719369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Schistosomiasis remains a neglected tropical disease of major public health concern with high levels of morbidity in various parts of the world. Although considerable efforts in implementing mass drug administration programs utilizing praziquantel have been deployed, schistosomiasis is still not contained. A vaccine may therefore be an essential part of multifaceted prevention control efforts. In the 1990s, a joint United Nations committee promoting parasite vaccines shortlisted promising candidates including for schistosomiasis discussed below. After examining the complexity of immune responses in human hosts infected with schistosomes, we review and discuss the antigen design and preclinical and clinical development of the four leading vaccine candidates: Sm-TSP-2 in Phase 1b/2b, Sm14 in Phase 2a/2b, Sm-p80 in Phase 1 preparation, and Sh28GST in Phase 3. Our assessment of currently leading vaccine candidates revealed some methodological issues that preclude a fair comparison between candidates and the rationale to advance in clinical development. These include (1) variability in animal models - in particular non-human primate studies - and predictive values of each for protection in humans; (2) lack of consensus on the assessment of parasitological and immunological parameters; (3) absence of reliable surrogate markers of protection; (4) lack of well-designed parasitological and immunological natural history studies in the context of mass drug administration with praziquantel. The controlled human infection model - while promising and unique - requires validation against efficacy outcomes in endemic settings. Further research is also needed on the impact of advanced adjuvants targeting specific parts of the innate immune system that may induce potent, protective and durable immune responses with the ultimate goal of achieving meaningful worm reduction.
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Mekonnen GG, Tedla BA, Pickering D, Becker L, Wang L, Zhan B, Bottazzi ME, Loukas A, Sotillo J, Pearson MS. Schistosoma haematobium Extracellular Vesicle Proteins Confer Protection in a Heterologous Model of Schistosomiasis. Vaccines (Basel) 2020; 8:E416. [PMID: 32722279 PMCID: PMC7563238 DOI: 10.3390/vaccines8030416] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/19/2020] [Accepted: 07/22/2020] [Indexed: 01/16/2023] Open
Abstract
Helminth parasites release extracellular vesicles which interact with the surrounding host tissues, mediating host-parasite communication and other fundamental processes of parasitism. As such, vesicle proteins present attractive targets for the development of novel intervention strategies to control these parasites and the diseases they cause. Herein, we describe the first proteomic analysis by LC-MS/MS of two types of extracellular vesicles (exosome-like, 120 k pellet vesicles and microvesicle-like, 15 k pellet vesicles) from adult Schistosoma haematobium worms. A total of 57 and 330 proteins were identified in the 120 k pellet vesicles and larger 15 k pellet vesicles, respectively, and some of the most abundant molecules included homologues of known helminth vaccine and diagnostic candidates such as Sm-TSP2, Sm23, glutathione S-transferase, saponins and aminopeptidases. Tetraspanins were highly represented in the analysis and found in both vesicle types. Vaccination of mice with recombinant versions of three of these tetraspanins induced protection in a heterologous challenge (S. mansoni) model of infection, resulting in significant reductions (averaged across two independent trials) in liver (47%, 38% and 41%) and intestinal (47%, 45% and 41%) egg burdens. These findings offer insight into the mechanisms by which anti-tetraspanin antibodies confer protection and highlight the potential that extracellular vesicle surface proteins offer as anti-helminth vaccines.
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Affiliation(s)
- Gebeyaw G. Mekonnen
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns 4878, Queensland, Australia; (G.G.M.); (B.A.T.); (D.P.); (L.B.); (J.S.)
- Department of Medical Parasitology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Bemnet A. Tedla
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns 4878, Queensland, Australia; (G.G.M.); (B.A.T.); (D.P.); (L.B.); (J.S.)
| | - Darren Pickering
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns 4878, Queensland, Australia; (G.G.M.); (B.A.T.); (D.P.); (L.B.); (J.S.)
| | - Luke Becker
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns 4878, Queensland, Australia; (G.G.M.); (B.A.T.); (D.P.); (L.B.); (J.S.)
| | - Lei Wang
- Texas Children’s Hospital Center for Vaccine Development, Department of Pediatrics and National School of Tropical Medicine, Baylor College of Medicine, Houston, TX 77030, USA; (L.W.); (B.Z.); (M.E.B.)
| | - Bin Zhan
- Texas Children’s Hospital Center for Vaccine Development, Department of Pediatrics and National School of Tropical Medicine, Baylor College of Medicine, Houston, TX 77030, USA; (L.W.); (B.Z.); (M.E.B.)
| | - Maria Elena Bottazzi
- Texas Children’s Hospital Center for Vaccine Development, Department of Pediatrics and National School of Tropical Medicine, Baylor College of Medicine, Houston, TX 77030, USA; (L.W.); (B.Z.); (M.E.B.)
| | - Alex Loukas
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns 4878, Queensland, Australia; (G.G.M.); (B.A.T.); (D.P.); (L.B.); (J.S.)
| | - Javier Sotillo
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns 4878, Queensland, Australia; (G.G.M.); (B.A.T.); (D.P.); (L.B.); (J.S.)
- Parasitology Reference and Research Laboratory, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain
| | - Mark S. Pearson
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns 4878, Queensland, Australia; (G.G.M.); (B.A.T.); (D.P.); (L.B.); (J.S.)
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Lei N, Liu FC, Ren CP, Shen JJ, Liu M. An Efficient Schistosoma japonicum Bivalent Membrane Protein Antigen DNA Vaccine Against Schistosomiasis in Mice. Med Sci Monit 2019; 25:9319-9326. [PMID: 31811711 PMCID: PMC6916134 DOI: 10.12659/msm.919195] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background Schistosomiasis is one of the most important infectious parasitic diseases in the world. The most important was to control schistosomiasis is through a combination of medical therapy and immunization. The membrane antigens Tsp2 and 29 from Schistosoma are promising anti-schistosomiasis vaccine candidates. Material/Methods In this study, the pcDNA3.1(+)-SjTsp2, pcDNA3.1(+)-Sj29, and pcDNA3.1 (+)-SjTsp2-29 eukaryotic expression vectors were successfully constructed as DNA vaccines, and the protective abilities of these vaccines were evaluated in mice. Results The results showed that vaccination with SjTsp2, Sj29, and SjTsp2-29 reduced parasite burden and hepatic pathology compared to the control group, and the protective effect of the bivalent SjTsp2-29 DNA vaccine was better than that of the univalent SjTsp2 or Sj29 DNA vaccines. We also found high levels of IgG, IgG1, and IgG2a against SjTsp2, Sj29, and SjTsp2-29 DNA vaccines, with high expression of IFN-γ and no IL-4 in the mice. Conclusions The double-membrane antigen DNA vaccine SjTsp2-29 elicited protection against Schistosoma infection and might serve as a vaccine candidate.
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Affiliation(s)
- Na Lei
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, Anhui, China (mainland).,Department of Physiology, Anhui Medical College, Hefei, Anhui, China (mainland)
| | - Feng-Chun Liu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, Anhui, China (mainland)
| | - Cui-Ping Ren
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, Anhui, China (mainland)
| | - Ji-Jia Shen
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, Anhui, China (mainland)
| | - Miao Liu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, Anhui, China (mainland)
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6
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Chen L, Chen Y, Zhang D, Hou M, Yang B, Zhang F, Zhang W, Luo X, Ji M, Wu G. Protection and immunological study on two tetraspanin-derived vaccine candidates against schistosomiasis japonicum. Parasite Immunol 2016; 38:589-98. [PMID: 27189226 DOI: 10.1111/pim.12338] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 05/12/2016] [Indexed: 12/29/2022]
Abstract
Tetraspanins (TSPs) are proteins found on the surface of helminth parasites of the genus Schistosoma and are regarded as potentially protective antigens. The large extracellular loop of Schistosoma mansoni tetraspanin-2, Sm-TSP-2, when fused to a thioredoxin partner and formulated with Freund's adjuvants, has been shown to be an efficacious vaccine against murine schistosomiasis. It is well recognized that CD4(+) T-cell-dependent immunity might play an important role against schistosomes; however, the contribution of CD8(+) T cells against multicellular pathogen is still uncertain. The exogenous protein-pulsed dendritic cells (DCs) can easily activate CD4(+) T cells response, while CD8(+) T cells response was relatively difficult to be induced. In this study, we evaluated the immunogenicity of TSP2HD antigen (hydrophilic domain of the S. japonicum tetraspanin-2) and TAT (the protein transduction domain of HIV-1)-coupled TSP2HD protein. As TAT-fused protein could promote major histocompatibility complex class I-dependent antigen presentation in vitro, TAT-TSP2HD-pulsed DCs induced stronger proliferation of schistosome-specific CD8(+) T cells compared with DCs incubated with TSP2HD alone. Vaccination with TAT-TSP2HD-pulsed DCs in vivo could improve disease outcome in S. japonicum-infected mice and was slightly superior to vaccination with DCs treated with TSP2HD. In summary, these data showed that TAT fusion proteins could help activate CD8(+) cells and Th1 cells and provide part protection against schistosome.
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Affiliation(s)
- L Chen
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, China.,Jiangsu Province Key Laboratory of Modern Pathogen Biology, Nanjing, Jiangsu, China
| | - Y Chen
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - D Zhang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, China.,Jiangsu Province Key Laboratory of Modern Pathogen Biology, Nanjing, Jiangsu, China
| | - M Hou
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, China.,Jiangsu Province Key Laboratory of Modern Pathogen Biology, Nanjing, Jiangsu, China
| | - B Yang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, China.,Jiangsu Province Key Laboratory of Modern Pathogen Biology, Nanjing, Jiangsu, China
| | - F Zhang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - W Zhang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - X Luo
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - M Ji
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, China. .,Jiangsu Province Key Laboratory of Modern Pathogen Biology, Nanjing, Jiangsu, China.
| | - G Wu
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, China.,Jiangsu Province Key Laboratory of Modern Pathogen Biology, Nanjing, Jiangsu, China
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Exploring molecular variation in Schistosoma japonicum in China. Sci Rep 2015; 5:17345. [PMID: 26621075 PMCID: PMC4664899 DOI: 10.1038/srep17345] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 10/26/2015] [Indexed: 12/12/2022] Open
Abstract
Schistosomiasis is a neglected tropical disease that affects more than 200 million people worldwide. The main disease-causing agents, Schistosoma japonicum, S. mansoni and S. haematobium, are blood flukes that have complex life cycles involving a snail intermediate host. In Asia, S. japonicum causes hepatointestinal disease (schistosomiasis japonica) and is challenging to control due to a broad distribution of its snail hosts and range of animal reservoir hosts. In China, extensive efforts have been underway to control this parasite, but genetic variability in S. japonicum populations could represent an obstacle to eliminating schistosomiasis japonica. Although a draft genome sequence is available for S. japonicum, there has been no previous study of molecular variation in this parasite on a genome-wide scale. In this study, we conducted the first deep genomic exploration of seven S. japonicum populations from mainland China, constructed phylogenies using mitochondrial and nuclear genomic data sets, and established considerable variation between some of the populations in genes inferred to be linked to key cellular processes and/or pathogen-host interactions. Based on the findings from this study, we propose that verifying intraspecific conservation in vaccine or drug target candidates is an important first step toward developing effective vaccines and chemotherapies against schistosomiasis.
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Toet H, Piedrafita DM, Spithill TW. Liver fluke vaccines in ruminants: strategies, progress and future opportunities. Int J Parasitol 2014; 44:915-27. [PMID: 25200351 DOI: 10.1016/j.ijpara.2014.07.011] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 07/18/2014] [Accepted: 07/21/2014] [Indexed: 12/27/2022]
Abstract
The development of a vaccine for Fasciola spp. in livestock is a challenge and would be advanced by harnessing our knowledge of acquired immune mechanisms expressed by resistant livestock against fluke infection. Antibody-dependent cell-mediated cytotoxicity directed to the surface tegument of juvenile/immature flukes is a host immune effector mechanism, suggesting that antigens on the surface of young flukes may represent prime candidates for a fluke vaccine. A Type 1 immune response shortly after fluke infection is associated with resistance to infection in resistant sheep, indicating that vaccine formulations should attempt to induce Type 1 responses to enhance vaccine efficacy. In cattle or sheep, an optimal fluke vaccine would need to reduce mean fluke burdens in a herd below the threshold of 30-54 flukes to ensure sustainable production benefits. Fluke infection intensity data suggest that vaccine efficacy of approximately 80% is required to reduce fluke burdens below this threshold in most countries. With the increased global prevalence of triclabendazole-resistant Fasciolahepatica, it may be commercially feasible in the short term to introduce a fluke vaccine of reasonable efficacy that will provide economic benefits for producers in regions where chemical control of new drug-resistant fluke infections is not viable. Commercial partnerships will be needed to fast-track new candidate vaccines using acceptable adjuvants in relevant production animals, obviating the need to evaluate vaccine antigens in rodent models.
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Affiliation(s)
- Hayley Toet
- Department of Agricultural Sciences and Centre for AgriBioscience, La Trobe University, Bundoora, Victoria 3083, Australia
| | - David M Piedrafita
- School of Applied Sciences and Engineering, Federation University, Churchill, Victoria 3842, Australia
| | - Terry W Spithill
- Department of Agricultural Sciences and Centre for AgriBioscience, La Trobe University, Bundoora, Victoria 3083, Australia.
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Sealey KL, Kirk RS, Walker AJ, Rollinson D, Lawton SP. Adaptive radiation within the vaccine target tetraspanin-23 across nine Schistosoma species from Africa. Int J Parasitol 2012; 43:95-103. [PMID: 23220042 DOI: 10.1016/j.ijpara.2012.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/14/2012] [Accepted: 11/15/2012] [Indexed: 12/27/2022]
Abstract
High levels of polymorphism in DNA sequences of tetraspanin-23 (TSP-23) were revealed within and between nine different species of Schistosoma from Africa including Schistosoma mansoni, Schistosoma rodhaini, Schistosoma margrebowiei, Schistosoma mattheei, Schistosoma intercalatum, Schistosoma haematobium, Schistosoma guineensis, Schistosoma curassoni and Schistosoma bovis. The greatest levels of diversity coincided with evidence of positive selection (d(N)/d(S)>1) within regions that code for extracellular loops of TSP-23 believed to interact with the host immune system. Kolaskar and Tongaonkar antigenicity predictions of protein sequences were compared across species and high levels of variation in antigenicity were also identified with each species which possessed their own unique antigenic profile. Phylogenetic analysis of TSP-23 proteins suggested evidence of convergent evolution in antigenic lineages as no true inter-species phylogenetic relationships were seen. This could be indicative of host-specific evolution of antigens in different species of schistosomes, a factor that should be considered carefully when developing vaccine targets.
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Affiliation(s)
- Katie L Sealey
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston Upon Thames, Surrey, UK
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Pearson MS, Pickering DA, McSorley HJ, Bethony JM, Tribolet L, Dougall AM, Hotez PJ, Loukas A. Enhanced protective efficacy of a chimeric form of the schistosomiasis vaccine antigen Sm-TSP-2. PLoS Negl Trop Dis 2012; 6:e1564. [PMID: 22428079 PMCID: PMC3302818 DOI: 10.1371/journal.pntd.0001564] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 01/27/2012] [Indexed: 01/04/2023] Open
Abstract
The large extracellular loop of the Schistosoma mansoni tetraspanin, Sm-TSP-2, when fused to a thioredoxin partner and formulated with Freund's adjuvants, has been shown to be an efficacious vaccine against murine schistosomiasis. Moreover, Sm-TSP-2 is uniquely recognised by IgG1 and IgG3 from putatively resistant individuals resident in S. mansoni endemic areas in Brazil. In the present study, we expressed Sm-TSP-2 at high yield and in soluble form in E. coli without the need for a solubility enhancing fusion partner. We also expressed in E. coli a chimera called Sm-TSP-2/5B, which consisted of Sm-TSP-2 fused to the immunogenic 5B region of the hookworm aspartic protease and vaccine antigen, Na-APR-1. Sm-TSP-2 formulated with alum/CpG showed significant reductions in adult worm and liver egg burdens in two separate murine schistosomiasis challenge studies. Sm-TSP-2/5B afforded significantly greater protection than Sm-TSP-2 alone when both antigens were formulated with alum/CpG. The enhanced protection obtained with the chimeric fusion protein was associated with increased production of anti-Sm-TSP-2 antibodies and IL-4, IL-10 and IFN-γ from spleen cells of vaccinated animals. Sera from 666 individuals from Brazil who were infected with S. mansoni were screened for potentially deleterious IgE responses to Sm-TSP-2. Anti-Sm-TSP-2 IgE to this protein was not detected (also shown previously for Na-APR-1), suggesting that the chimeric antigen Sm-TSP-2/5B could be used to safely and effectively vaccinate people in areas where schistosomes and hookworms are endemic. There are currently no vaccines available to combat helminth (worm) infections in humans. The most devastating of the diseases caused by human helminths are schistosomiasis (or bilharzia) and hookworm disease. By fusing one of the lead schistosomiasis vaccine antigens, Sm-TSP-2, with a protective fragment from one of the lead hookworm vaccine antigens, Na-APR-1, we have produced a chimeric vaccine, termed Sm-TSP-2/5B that might provide protection against two debilitating and co-endemic neglected tropical diseases. Sm-TSP-2/5B provided increased protection compared to Sm-TSP-2 alone when formulated with human approved adjuvants and tested in a mouse model of schistosomiasis. Moreover, IgE against Sm-TSP-2 or Na-APR-1 has not been detected in the blood of residents from an area in Brazil that is endemic for schistosomes and hookworms, indicating that vaccines based on these molecules would be unlikely to generate allergic reactions in recipients from developing countries.
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MESH Headings
- Adjuvants, Immunologic/administration & dosage
- Adolescent
- Adult
- Aged
- Alum Compounds/administration & dosage
- Animals
- Antibodies, Helminth/blood
- Antigens, Helminth/administration & dosage
- Antigens, Helminth/genetics
- Antigens, Helminth/immunology
- Aspartic Acid Proteases/administration & dosage
- Aspartic Acid Proteases/genetics
- Aspartic Acid Proteases/immunology
- Brazil
- Child
- Child, Preschool
- Cytokines/metabolism
- Disease Models, Animal
- Escherichia coli/genetics
- Female
- Gene Expression
- Humans
- Immunoglobulin G/blood
- Infant
- Leukocytes, Mononuclear/immunology
- Male
- Mice
- Mice, Inbred C57BL
- Middle Aged
- Oligodeoxyribonucleotides/administration & dosage
- Recombinant Fusion Proteins/administration & dosage
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- Schistosomiasis/immunology
- Schistosomiasis/prevention & control
- Spleen/immunology
- Tetraspanins/administration & dosage
- Tetraspanins/genetics
- Tetraspanins/immunology
- Vaccines, Synthetic/administration & dosage
- Vaccines, Synthetic/immunology
- Young Adult
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Affiliation(s)
- Mark S. Pearson
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
| | - Darren A. Pickering
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
| | - Henry J. McSorley
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
| | - Jeffrey M. Bethony
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington D.C., United States of America
| | - Leon Tribolet
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
| | - Annette M. Dougall
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
| | - Peter J. Hotez
- Department of Pediatrics and Molecular Virology and Microbiology, and National School of Tropical Medicine, Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alex Loukas
- Queensland Tropical Health Alliance and School of Public Health and Tropical Medicine, James Cook University, Cairns, Queensland, Australia
- * E-mail:
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Cupit PM, Steinauer ML, Tonnessen BW, Agola LE, Kinuthia JM, Mwangi IN, Mutuku MW, Mkoji GM, Loker ES, Cunningham C. Polymorphism associated with the Schistosoma mansoni tetraspanin-2 gene. Int J Parasitol 2011; 41:1249-52. [PMID: 21889508 PMCID: PMC3188324 DOI: 10.1016/j.ijpara.2011.07.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 07/24/2011] [Accepted: 07/27/2011] [Indexed: 10/17/2022]
Abstract
A vaccine against schistosomiasis would contribute significantly to reducing the 3-70 million disability-adjusted life years lost annually to the disease. Towards this end, inoculation with the large extracellular loop (EC-2) of Schistosoma mansoni tetraspanin-2 protein (Sm-TSP-2) has proved effective in reducing worm and egg burdens in S. mansoni-infected mice. The EC-2 loop of Schistosoma japonicum TSP-2, however, has been found to be highly polymorphic, perhaps diminishing the likelihood that this antigen can be used for vaccination against this species. Here, we examine polymorphism of the EC-2 of Sm-TSP-2 in genetically unique worms derived from six individuals from Kisumu, Kenya.
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Affiliation(s)
- Pauline M. Cupit
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | | | - Bradley W. Tonnessen
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - L. Eric Agola
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Joseph M. Kinuthia
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Ibrahim N. Mwangi
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Martin W. Mutuku
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Gerald M. Mkoji
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Eric S. Loker
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Charles Cunningham
- Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
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Inconsistent protective efficacy and marked polymorphism limits the value of Schistosoma japonicum tetraspanin-2 as a vaccine target. PLoS Negl Trop Dis 2011; 5:e1166. [PMID: 21655308 PMCID: PMC3104969 DOI: 10.1371/journal.pntd.0001166] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 03/16/2011] [Indexed: 01/11/2023] Open
Abstract
Background Schistosoma mansoni tetraspanin 2 (Sm-TSP-2) has been shown to be strongly recognized by IgG1 and IgG3 antibodies from individuals putatively resistant to schistosome infection, but not chronically infected people, and to induce high levels of protection against challenge infection in the murine model of schistosomiasis. Amplification by PCR of homologous sequences from male and female S. japonicum worms showed the presence of 7 different clusters or subclasses of S. japonicum TSP-2. We determined the protective efficacy of one subclass – Sj-TSP-2e. Methodology/Principal Findings Following the alignment of 211 cDNAs, we identified 7 clusters encoding S. japonicum TSP-2 (Sj-TSP-2) based on sequence variation in the large extracellular loop (LEL) region with differing frequency of transcription in male and female worms. Quantitative PCR analysis revealed elevated expression of Sj-TSP-2 in adult worms compared with other life cycle stages. We expressed in E. coli the LEL region of one of the clusters which exhibited a high frequency of transcription in female worms, and showed the purified recombinant protein (Sj-TSP-2e) was recognised by 43.1% of sera obtained from confirmed schistosomiasis japonica patients. Vaccination of mice with the recombinant protein induced high levels of IgG1 and IgG2 antibodies, but no consistent protective efficacy against challenge infection was elicited in three independent trials. Conclusions/Significance The highly polymorphic nature of the Sj-TSP-2 gene at the transcriptional level may limit the value of Sj-TSP-2 as a target for future S. japonicum vaccine development. Schistosoma mansoni tetraspanin 2 (Sm-TSP-2) is considered a lead target for vaccine development against schistosomiasis mansoni because: (1) It is located in the schistosome tegument and is involved in tegument formation; (2) It is strongly recognized by IgG1 and IgG3 antibodies from individuals putatively resistant to schistosome infection, but not chronically infected people, and (3) It induces high levels of protection against challenge infection in the mouse model. We amplified 211 homologous TSP-2 sequences from male and female S. japonicum worms, which revealed 7 different cDNA subclasses. We expressed in E. coli a region of one of the clusters which exhibited a high frequency of transcription in female worms, and showed the purified recombinant protein (Sj-TSP-2e) was recognised by 43.1% of sera obtained from confirmed schistosomiasis japonica patients. Vaccination of mice with the recombinant protein induced high levels of IgG1 and IgG2 antibodies, but no consistent protective efficacy against challenge infection was elicited in three independent trials. The highly polymorphic nature of the Sj-TSP-2 gene at the transcriptional level may limit the value of Sj-TSP-2 as a target for future S. japonicum vaccine development. Further analysis of the distribution of the different subclasses/alleles of the Sj-TSP-2 gene in S. japonicum populations from different endemic areas would be informative.
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Developing vaccines to combat hookworm infection and intestinal schistosomiasis. Nat Rev Microbiol 2010; 8:814-26. [PMID: 20948553 DOI: 10.1038/nrmicro2438] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hookworm infection and schistosomiasis rank among the most important health problems in developing countries. Both cause anaemia and malnutrition, and schistosomiasis also results in substantial intestinal, liver and genitourinary pathology. In sub-Saharan Africa and Brazil, co-infections with the hookworm, Necator americanus, and the intestinal schistosome, Schistosoma mansoni, are common. The development of vaccines for these infections could substantially reduce the global disability associated with these helminthiases. New genomic, proteomic, immunological and X-ray crystallographic data have led to the discovery of several promising candidate vaccine antigens. Here, we describe recent progress in this field and the rationale for vaccine development.
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