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Zerna G, Spithill TW, Beddoe T. Current Status for Controlling the Overlooked Caprine Fasciolosis. Animals (Basel) 2021; 11:1819. [PMID: 34207215 PMCID: PMC8235714 DOI: 10.3390/ani11061819] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 01/17/2023] Open
Abstract
The disease fasciolosis is caused by the liver flukes Fasciola hepatica and F. gigantica, which infect a wide range of mammals and production livestock, including goats. These flatworm parasites are globally distributed and predicted to cost the livestock industry a now conservative USD 3 billion per year in treatment and lowered on-farm productivity. Infection poses a risk to animal welfare and results in lowered fertility rates and reduced production yields of meat, milk and wool. This zoonotic disease is estimated to infect over 600 million animals and up to 2.4 million humans. Current and future control is threatened with the global emergence of flukes resistant to anthelmintics. Drug resistance calls for immediate on-farm parasite management to ensure treatments are effective and re-infection rates are kept low, while a sustainable long-term control method, such as a vaccine, is being developed. Despite the recent expansion of the goat industry, particularly in developing countries, there are limited studies on goat-focused vaccine control studies and the effectiveness of drug treatments. There is a requirement to collate caprine-specific fasciolosis knowledge. This review will present the current status of liver fluke caprine infections and potential control methods for application in goat farming.
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Affiliation(s)
| | | | - Travis Beddoe
- Department of Animal, Plant and Soil Sciences and Centre for AgriBioscience, La Trobe University, Bundoora, Victoria 3083, Australia; (G.Z.); (T.W.S.)
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Wesołowska A, Kozak Ljunggren M, Jedlina L, Basałaj K, Legocki A, Wedrychowicz H, Kesik-Brodacka M. A Preliminary Study of a Lettuce-Based Edible Vaccine Expressing the Cysteine Proteinase of Fasciola hepatica for Fasciolosis Control in Livestock. Front Immunol 2018; 9:2592. [PMID: 30483259 PMCID: PMC6244665 DOI: 10.3389/fimmu.2018.02592] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 10/22/2018] [Indexed: 11/16/2022] Open
Abstract
Oral vaccination with edible vaccines is one of the most promising approaches in modern vaccinology. Edible vaccines are an alternative to conventional vaccines, which are typically delivered by injection. Here, freeze-dried transgenic lettuce expressing the cysteine proteinase of the trematode Fasciola hepatica (CPFhW) was used to orally vaccinate cattle and sheep against fasciolosis, which is the most important trematode disease due to the parasite's global distribution, wide spectrum of host species and significant economic losses of farmers. In the study, goals such as reducing the intensity of infection, liver damage and F. hepatica fecundity were achieved. Moreover, we demonstrated that the host sex influenced the outcome of infection following vaccination, with female calves and male lambs showing better protection than their counterparts. Since differences occurred following vaccination and infection, different immunization strategies should be considered for different sexes and host species when developing new control methods. The results of the present study highlight the potential of oral vaccination with plant-made and plant-delivered vaccines for F. hepatica infection control.
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Affiliation(s)
- Agnieszka Wesołowska
- Polish Academy of Sciences, Witold Stefanski Institute of Parasitology, Warsaw, Poland
| | | | - Luiza Jedlina
- Polish Academy of Sciences, Witold Stefanski Institute of Parasitology, Warsaw, Poland
| | - Katarzyna Basałaj
- Polish Academy of Sciences, Witold Stefanski Institute of Parasitology, Warsaw, Poland
| | - Andrzej Legocki
- Polish Academy of Sciences, Institute of Bioorganic Chemistry, Poznan, Poland
| | - Halina Wedrychowicz
- Polish Academy of Sciences, Witold Stefanski Institute of Parasitology, Warsaw, Poland
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Wesołowska A, Basałaj K, Norbury LJ, Sielicka A, Wędrychowicz H, Zawistowska-Deniziak A. Vaccination against Fasciola hepatica using cathepsin L3 and B3 proteases delivered alone or in combination. Vet Parasitol 2017; 250:15-21. [PMID: 29329618 DOI: 10.1016/j.vetpar.2017.12.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 11/29/2022]
Abstract
No licensed vaccine is currently available for prevention of Fasciola hepatica infections. However, considering the alarming increase in drug resistance, there is an urgent need for a safe and fully effective vaccine against fasciolosis. Here, we tested if cathepsins L (FhCL3-1, FhCL3-2) and B (FhCB3) secreted by juvenile liver flukes are viable vaccine targets when delivered alone or in combination in a rat model. Since control over the early immune response is crucial for parasite's establishment in its host, it was hypothesised that targeting fluke juvenile stages may prove beneficial. Moreover, it was assumed that selected antigens will act in a cumulative manner to interfere with liver fluke migration and thereby will reduce F. hepatica infection. Recombinant FhCL3-1 and FhCL3-2 delivered alone reduced liver fluke burdens by 47 % and 63 %, respectively. A trivalent vaccine containing rFhCL3-1/CL3-2/CB3 did not increase the protective vaccine efficacy compared to the rFhCL3-2 vaccinated group (53 %), although, reductions in liver fluke wet weight (statistically significant) and liver damage score were most pronounced. Further, the highest IgG1 and IgG2a levels were seen in rFhCL3-2 vaccinated rats, the group for which the highest reduction in worm burden was demonstrated. Moreover, IgG1 and IgG2a levels in vaccinated rats were significantly elevated compared to those reported for control groups up to 4 week post-infection. While the mechanism of protection remains unknown, it appears that it depends on vaccine-induced antibodies directed against cathepsins. The obtained results imply that F. hepatica juvenile-specific cathepsins are promising vaccine candidates that induce responses that successfully target early migratory liver fluke stages. Now, the challenge is to evaluate these juvenile-specific cathepsins for use in livestock.
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Affiliation(s)
- Agnieszka Wesołowska
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences,Twarda 51/55, 00-818, Warsaw, Poland
| | - Katarzyna Basałaj
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences,Twarda 51/55, 00-818, Warsaw, Poland
| | - Luke J Norbury
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences,Twarda 51/55, 00-818, Warsaw, Poland; School of Science, RMIT University, Bundoora, Victoria, 3083, Australia
| | - Alicja Sielicka
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences,Twarda 51/55, 00-818, Warsaw, Poland
| | - Halina Wędrychowicz
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences,Twarda 51/55, 00-818, Warsaw, Poland
| | - Anna Zawistowska-Deniziak
- Witold Stefański Institute of Parasitology, Polish Academy of Sciences,Twarda 51/55, 00-818, Warsaw, Poland.
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4
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Immunization with Fasciola hepatica thioredoxin glutathione reductase failed to confer protection against fasciolosis in cattle. Vet Parasitol 2016; 224:13-19. [DOI: 10.1016/j.vetpar.2016.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 05/03/2016] [Accepted: 05/04/2016] [Indexed: 11/22/2022]
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Induction of immunity in sheep toFasciola hepaticawith mimotopes of cathepsin L selected from a phage display library. Parasitology 2008; 135:1437-45. [DOI: 10.1017/s003118200800471x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
SUMMARYAn M13 phage random 12-mers peptide library was used to screen cathepsin L mimotopes ofFasciola hepaticaand to evaluate their immunogenicity in sheep. Seven clones showed positive reactivity to a rabbit anti-cathepsin L1/L2 antiserum in ELISA, and their amino acid sequences deduced by DNA sequencing were tentatively mapped on the protein. Twenty sheep were randomly allocated into 4 groups of 5 animals each, for immunization with 1×1014phage particles of clones 1, 20, a mixture of 7 clones and PBS, without adjuvant at the beginning, and 4 weeks later. All groups were challenged with 300 metacercariae at week 6 and slaughtered 16 weeks later. The mean worm burdens after challenge were reduced by 47·61% and 33·91% in sheep vaccinated with clones 1 and 20, respectively; no effect was observed in animals inoculated with the clone mixture. Also, a significant reduction in worm size and burden was observed for those sheep immunized with clone 1. Animals receiving clone 20, showed a significant reduction in egg output. Immunization induced a reduction of egg viability ranging from 58·92 to 82·11%. Furthermore, vaccinated animals produced clone-specific antibodies which were boosted after challenge with metacercariae ofF. hepatica.
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Wedrychowicz H, Kesik M, Kaliniak M, Kozak-Cieszczyk M, Jedlina-Panasiuk L, Jaros S, Plucienniczak A. Vaccine potential of inclusion bodies containing cysteine proteinase of Fasciola hepatica in calves and lambs experimentally challenged with metacercariae of the fluke. Vet Parasitol 2007; 147:77-88. [PMID: 17481823 DOI: 10.1016/j.vetpar.2007.03.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2006] [Revised: 03/18/2007] [Accepted: 03/21/2007] [Indexed: 10/23/2022]
Abstract
Despite intensive research efforts, progress in the development of effective anti-Fasciola hepatica vaccine has not been satisfactory. However, it has been found that cysteine proteinases of F. hepatica are very important candidates for a vaccine antigen because of their role in fluke biology and in the host-parasite relationship. In our previous experiments we found that recombinant cysteine proteinase which we have cloned from adult F. hepatica (CPFhW) can protect rats against the liver fluke infection when administered intramuscularly or when given intranasally in the form of cDNA. In the present experiments we aimed to evaluate the protectivity of the mucosal vaccination in calves and lambs with inclusion bodies containing recombinant CPFhW using different vaccination doses and various sites of antigen delivery. Female calves vaccinated intranasally with two doses of 300 microg of the recombinant CPFhW showed 54.2% protection against the subsequent challenge of 400 metacercariae (mc). Flukes which developed in vaccinated calves showed a reduction of reproductive potential. Male Corriedale lambs vaccinated at the age of 4 months demanded three doses of the antigen to gain 56.5% of protection to a challenge with 250 mc of F. hepatica. Vaccinated animals showed significantly lower blood eosinophil counts. No correlation was found between serum and mucosal IgG or IgA reacting with F. hepatica ES antigens and the protection level.
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Affiliation(s)
- H Wedrychowicz
- W. Stefanski Institute of Parasitology, Twarda 51/55, 00-818 Warszawa, Poland.
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Kumar A, Kumar K, Korde R, Puri SK, Malhotra P, Singh Chauhan V. Falcipain-1, a Plasmodium falciparum cysteine protease with vaccine potential. Infect Immun 2007; 75:2026-34. [PMID: 17242063 PMCID: PMC1865716 DOI: 10.1128/iai.01533-06] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 10/24/2006] [Accepted: 12/21/2006] [Indexed: 11/20/2022] Open
Abstract
Cysteine proteases (falcipains) of Plasmodium falciparum are potential targets for antimalarial chemotherapy, since they have been shown to be involved in important cellular functions such as hemoglobin degradation and invasion/rupture of red blood cells during parasite life cycle. The role of falcipain-1 at the asexual blood stages of the parasite still remains uncertain. This is mainly due to a lack of methods to prepare this protein in an active form. In order to obtain biologically active falcipain-1, a number of falcipain-1 constructs were designed and a systematic assessment of the refolding conditions was done. We describe here the expression, purification, and characterization of a falcipain-1 construct encoding mature falcipain-1 and 35 amino acids from the C-terminal of the pro domain. Recombinant falcipain-1 was overexpressed in the form of inclusion bodies, solubilized, and purified by Ni(2+)-nitrilotriacetic acid affinity chromatography under denaturing conditions. A systemic approach was then followed to optimize refolding parameters. An optimum refolding condition was obtained, and the yield of the purified refolded falcipain-1 was approximately 1 mg/liter. Activity of the protein was analyzed by fluorometric and gelatin degradation assays. Immunolocalization studies using anti-falcipain-1 sera revealed a distinct staining at the apical end of the P. falciparum merozoites. Previous studies using falcipain-1-specific inhibitors have suggested a role of falcipain-1 in merozoite invasion. Based on its localization and its role in invasion, we analyzed the immunogenicity of falcipain-1 in mice, followed by heterologous challenge with Plasmodium yoelii sporozoites. Our results suggest a possible role of falcipain-1 in merozoite invasion.
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Affiliation(s)
- Amit Kumar
- International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India
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Bentancor A, Piacenza L, Carmona C. Immunization with cathepsin L proteinases CL1 and CL2 secreted by Fasciola hepatica elicit a preferential type 1 response based on IgG2a antibodies in rats. J Helminthol 2002; 76:199-205. [PMID: 12363372 DOI: 10.1079/joh2002123] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cathepsin L proteinases (CL1 and CL2), the major components of Fasciola hepatica excretion/secretion products (E/S) are considered potential antigens of a vaccine against fascioliasis. The humoral response elicited by CL1 and CL2 in rats either immunized with the enzymes or infected with F. hepatica has been analysed, examining specific IgE and IgG subclass dynamics. The experiment was continued for 10 weeks and peripheral blood eosinophilia was also determined. Infected rats presented peaks of eosinophilia at weeks 3 and 7 post-infection, while those immunized with CL1 and CL2 were no different from controls. Total IgE in infected rats increased up to week 5, reaching 30 microg(-1) in some cases, then decreased slowly and rising again towards the end of the experiment. Determination of specific IgE, carried out in sera previously absorbed with Protein G-Sepharose, reached a peak in infected rats between weeks 2 and 5, depending on the individual. In immunized rats both total and specific IgE levels remained around the pre-immunization values. With regard to the IgG subclass responses to E/S products, in infected rats IgG1 predominated over IgG2a, and the reverse was true in rats immunized with CL1 and CL2 and tested against the respective antigens. In all cases an increase in IgG1 and IgG2a antibody titres was seen, with maximum levels being reached later (weeks 6-7) in infected rats than in immunized ones (weeks 4-5). No IgG2b or IgG2c responses were detected in any of the groups studied.
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Affiliation(s)
- A Bentancor
- Unidad de Biología Parasitaria, Instituto de Higiene, Facultad de Ciencias, Av. A. Navarro 3051, CP 11600 Montevideo, Uruguay
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Prowse RK, Chaplin P, Robinson HC, Spithill TW. Fasciola hepatica cathepsin L suppresses sheep lymphocyte proliferation in vitro and modulates surface CD4 expression on human and ovine T cells. Parasite Immunol 2002; 24:57-66. [PMID: 11874560 DOI: 10.1046/j.0141-9838.2001.00438.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fasciola hepatica infection has been shown to suppress sheep lymphocyte proliferation in vitro and this is at least partially attributable to excretory/secretory products (ES) released by F. hepatica parasites. We identified a suppressive component in ES by analysing the effect of ES fractions, separated by gel filtration, on the proliferation of sheep T cells in vitro. A major proportion of the suppressive activity in ES was shown to coelute with the cathepsin L proteases: E64, a cysteine protease inhibitor, blocked the suppressive activity of cathepsin L. In order to identify possible mechanisms by which cathepsin L could suppress T cell proliferation, the effect of ES and F. hepatica recombinant cathepsin L (rFhCatL) on the expression of 22 different sheep T cell surface markers was analysed by flow cytometry. Incubation of sheep T cells with ES or two rFhCatL significantly reduced surface CD4 expression and this effect was prevented in the presence of E64. In similar experiments with human T lymphocytes, ES and rFhCatL were shown to down regulate surface CD4 expression. These results show that F. hepatica cathepsin L both suppresses sheep T cell proliferation and reduces surface CD4 expression on both human and ovine T cells.
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Affiliation(s)
- Rhoda K Prowse
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
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Marcet R, Díaz A, Arteaga E, Finlay CM, Sarracent J. Passive protection against fasciolosis in mice by immunization with a monoclonal antibody (ES-78 MoAb). Parasite Immunol 2002; 24:103-8. [PMID: 11874565 DOI: 10.1046/j.0141-9838.2001.00443.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recently, we reported a partial characterization of the epitope recognized by the ES-78 monoclonal antibody (MoAb). This monoclonal antibody was obtained from spleen lymphocytes of a mouse immunized with excretory-secretory antigens of Fasciola hepatica adult worms. In the present study, we report the results obtained in experiments of passive protection using this MoAb in BALB/c mice infected with 15 Fasciola hepatica metacercariae. The monoclonal antibody was able to reduce the parasite burden when administered 24 h before challenge but not when delivered 7 days after challenge. The antibody recognition of digestive tract structures in 3-week-old parasites was demonstrated by immune histochemical techniques. The antigens purified by affinity chromatography using this antibody had molecular weights of 14-20, 25-29 and 36-45 kDa and demonstrated proteinase activity similar to cathepsin L. These results suggest that the antigens carrying the epitope recognized by the ES-78 MoAb may be used as target in the protection against fasciolosis.
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Affiliation(s)
- Ricardo Marcet
- Departamento de Parasitología, Instituto de Medicina Tropical 'Pedro Kourí', Ciudad de la Habana, Cuba.
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Chlichlia K, Bahgat M, Ruppel A, Schirrmacher V. DNA vaccination with asparaginyl endopeptidase (Sm32) from the parasite Schistosoma mansoni: anti-fecundity effect induced in mice. Vaccine 2001; 20:439-47. [PMID: 11672907 DOI: 10.1016/s0264-410x(01)00345-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
DNA-based vaccine technology was used to induce an immune response in mice against a schistosome cysteine proteinase, asparaginyl endopeptidase (Sm32). The cDNA coding for Sm32 was cloned in a mammalian expression vector under control of the CMV promoter/enhancer and expressed for the first time in transfected mammalian cells as well as in mice immunized with the Sm32-encoding DNA construct. These mice developed antibodies which recognized the native protein not only in homogenates of Schistosoma mansoni worms but also in the gut on cryostat sections of the parasites. This DNA vaccine led to an anti-fecundity effect: female worms of a challenge infection produced 37% less eggs than those growing in naïve mice. The results suggest that Sm32 may be a candidate antigen for the generation of an anti-pathology vaccine against schistosomes.
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Affiliation(s)
- K Chlichlia
- Department of Tropical Hygiene, University of Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
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Dowd AJ, Dooley M, Fágáin C, Dalton JP. Stability studies on the cathepsin L proteinase of the helminth parasite, Fasciola hepatica. Enzyme Microb Technol 2000; 27:599-604. [PMID: 11024523 DOI: 10.1016/s0141-0229(00)00259-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Fasciola hepatica, the liver fluke, secretes a cathepsin L cysteine proteinase. The enzyme is active over the pH range 5-9 and is remarkably stable at 37 degrees C, pH 7.0, in contrast to mammalian cathepsin Ls that are active in the acidic pH range and are inactivated within 15 min at neutral pH. The liver fluke proteinase is also very tolerant of organic solvents, particularly dimethylformamide. However, it is completely inactivated by 1 mM Hg(2+) and adversely affected by other heavy metals and divalent cations. Addition of glycerol and EDTA enhanced the liver fluke enzyme's stability at 50 degrees C, while glucose and glycerol protected the enzyme from inactivation by repeated freeze-thawing. The high stability of liver fluke cathepsin L suggests that it may have potential for use in bioindustrial applications.
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Affiliation(s)
- AJ Dowd
- School of Biotechnology, Dublin City University, 9, Republic of, Dublin, Ireland
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Piacenza L, Acosta D, Basmadjian I, Dalton JP, Carmona C. Vaccination with cathepsin L proteinases and with leucine aminopeptidase induces high levels of protection against fascioliasis in sheep. Infect Immun 1999; 67:1954-61. [PMID: 10085042 PMCID: PMC96552 DOI: 10.1128/iai.67.4.1954-1961.1999] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/1998] [Accepted: 01/26/1999] [Indexed: 11/20/2022] Open
Abstract
The potential of different parasite proteinases for use as vaccine candidates against fascioliasis in sheep was studied by vaccinating animals with the cathepsin L proteinases CL1 and CL2 and with leucine aminopeptidase (LAP) purified from adult flukes. In the first trial, sheep were immunized with CL1 or CL2 and the mean protection levels obtained were 33 and 34%, respectively. Furthermore, a significant reduction in egg output was observed in sheep vaccinated either with CL1 (71%) or with CL2 (81%). The second trial was performed to determine the protective potential of the two cathepsin L proteinases assayed together, as well as in combination with LAP, and of LAP alone. The combination of CL1 and CL2 induced higher levels of protection (60%) than those produced when these enzymes were administered separately. Those sheep that received the cocktail vaccine including CL1, CL2, and LAP were significantly protected (78%) against metacercarial challenge, but vaccination with LAP alone elicited the highest level of protection (89%). All vaccine preparations induced high immunoglobulin G titers which were boosted after the challenge infection, but no correlations between antibody titers and worm burdens were found. However, the sera of those animals vaccinated with LAP contained LAP-neutralizing antibodies. Reduced liver damage, as assessed by the level of the liver enzyme gamma-glutamyl transferase, was observed in the groups vaccinated with CL1, CL2, and LAP or with LAP alone.
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Affiliation(s)
- L Piacenza
- Unidad de Biología Parasitaria, Facultad de Ciencias, Instituto de Higiene, Montevideo, Uruguay
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Abstract
Infection of ruminants by Fasciola spp continues to cause large economic losses worldwide. Recent results from several laboratories have demonstrated that animals can be significantly protected against infection by vaccination with defined Fasciola antigens. Apart from reducing fluke burdens, some vaccines can elicit a concurrent reduction in parasite egg production. The expectation of a commercially feasible vaccine that might also reduce parasite transmission in the field is now realistic, although major hurdles still exist. Here, Terry Spithill and John Dalton review the results of several recent vaccine trials and discuss the future prospects for vaccine development.
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Affiliation(s)
- T W Spithill
- Department of Biochemistry and Molecular Biology, Monash University, Monash Australia
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15
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Piacenza L, Acosta D, Dowd A, McGonicle S, Dalton J, Carmona C. Proteinases secreted by Fasciola hepatica: time course of the inhibitory effect of serum from experimentally infected rabbits demonstrated by gelatin-substrate polyacrylamide gel electrophoresis. J Helminthol 1997; 71:333-8. [PMID: 9443952 DOI: 10.1017/s0022149x00016151] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Fasciola hepatica secretes proteolytic enzymes to aid it to penetrate and migrate through the host tissues. Two of these proteinases have been purified and shown to be cathepsin L-like, and are termed, CL1 (27.5 kD) and CL2 (29 kD). The immunogenicity of these proteinases was investigated over the course of an experimental infection and following drug treatment. Four groups of rabbits were studied: group 1: orally infected with 50 metacercariae; group 2: infected and treated 8 weeks after infection; group 3: infected, treated at week 8 and reinfected at week 13 and group 4: non-infected control group. Sera were collected weekly from each group until week 20 postinfection. CL1 and CL2 were incubated with the different sera and then analysed by gelatin substrate polyacrylamide gel electrophoresis (GS-PAGE). Analysis of groups 1, 2 and 3 showed that CL1 and CL2 neutralizing antibodies appear at week 5 post-infection. In group 1, these remained throughout the 20 weeks of infection. In group 2, neutralizing antibodies disappeared at week 13, that is, 5 weeks after anti-Fasciola treatment. In group 3, CL1 and CL2 neutralizing antibodies disappeared at week 13 but reappeared by week 15, that is 2 weeks after reinfection. Pooled sera from group 4, showed no inhibitory capacity. ELISA results using CL1 and CL2 as antigen, correlate very well with the inhibitiory time course observed by GS-PAGE. These results suggest that purified cathepsin Ls are antigenic molecules recognized early in the infective process and capable of inducing a specific humoral response, strong enough to neutralize, at least partially, their enzymatic activity.
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Affiliation(s)
- L Piacenza
- Unidad de Biología Parasitaria, Facultad de Ciencias, Instituto de Higiene, Av. A. Navarro 3051, CP 11600, Montevideo, Uruguay
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Dowd AJ, Tort J, Roche L, Ryan T, Dalton JP. Isolation of a cDNA encoding Fasciola hepatica cathepsin L2 and functional expression in Saccharomyces cerevisiae. Mol Biochem Parasitol 1997; 88:163-74. [PMID: 9274877 DOI: 10.1016/s0166-6851(97)00090-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cathepsin L2 is a major cysteine proteinase secreted by adult Fasciola hepatica. The enzyme differs from other reported cathepsin Ls in that it can cleave peptide substrates that contain proline in the P2 position. A cDNA was isolated from an expression library by immunoscreening with antiserum prepared against purified native cathepsin L2. This cDNA was sequenced and shown to encode a complete preprocathepsin L proteinase. Functionally active recombinant cathepsin L proteinase was expressed and secreted by Saccharomyces cerevisiae transformed with the cDNA. The recombinant enzyme was purified from large-scale fermentation broths using ultrafiltration and gel filtration chromatography on Sephacryl S200 HR columns. NH2-terminal amino acid sequencing showed that the cleavage point for activation of the recombinant pro-enzyme is identical to that of the F. hepatica-produced cathepsin L2. The mature active recombinant proteinase behaved similarly to the native enzyme when analysed by SDS-PAGE, immunoblotting and zymography and also cleaved peptides containing proline in the P2 position. Finally, the recombinant cathepsin L2 cleaved fibrinogen to form a fibrin clot, a property we described for F. hepatica cathepsin L2.
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Affiliation(s)
- A J Dowd
- School of Biological Sciences, Dublin City University, Glasnevin, Ireland
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18
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Dalton JP, McGonigle S, Rolph TP, Andrews SJ. Induction of protective immunity in cattle against infection with Fasciola hepatica by vaccination with cathepsin L proteinases and with hemoglobin. Infect Immun 1996; 64:5066-74. [PMID: 8945548 PMCID: PMC174490 DOI: 10.1128/iai.64.12.5066-5074.1996] [Citation(s) in RCA: 186] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Two cathepsin L proteinases, cathepsin L1 and cathepsin L2, secreted by liver flukes may be involved in tissue penetration, nutrition, and protection from immune attack. To ascertain the immunoprophylactic potential of these proteinases, and of another molecule, liver fluke hemoglobin (Hb), we performed vaccine trials in cattle. In the first vaccine trial various doses of cathepsin L1 were tested. The mean protection level obtained was 53.7%. In a second vaccine trial cathepsin L1 and Hb elicited 42.5 and 43.8% protection levels, respectively, while a combination of the two molecules induced a significantly higher level of protection (51.9%). Cathepsin L2 was not examined alone; however, vaccination of cattle with a combination of cathepsin L2 and Hb elicited the highest level of protection (72.4%). The animals that received cathepsin L1-Hb or cathepsin L2-Hb showed reduced liver damage as assessed by serum glutamic dehydrogenase and gamma-glutamyl transferase levels. Furthermore, a reduced viability was observed for fluke eggs recovered from all vaccine groups. This anti-embryonation effect of vaccination was particularly evident in the group that received cathepsin L2-Hb where >98% of the eggs recovered did not embryonate to miracidia. Although all vaccine preparations induced high antibody titers which were boosted following the challenge infection, there was no correlation between antibody titers and protection. The results of these trials demonstrate that cathepsin Ls and Hb could form the basis of a molecular vaccine that would not only reduce parasite burden but would also prevent transmission of liver fluke disease.
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Affiliation(s)
- J P Dalton
- School of Biological Sciences, Dublin City University, Republic of Ireland.
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