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Pękacz M, Basałaj K, Młocicki D, Kamaszewski M, Carretón E, Morchón R, Wiśniewski M, Zawistowska-Deniziak A. Molecular insights and antibody response to Dr20/22 in dogs naturally infected with Dirofilaria repens. Sci Rep 2024; 14:12979. [PMID: 38839868 PMCID: PMC11153217 DOI: 10.1038/s41598-024-63523-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 05/29/2024] [Indexed: 06/07/2024] Open
Abstract
Subcutaneous dirofilariasis, caused by the parasitic nematode Dirofilaria repens, is a growing concern in Europe, affecting both dogs and humans. This study focused on D. repens Dr20/22, a protein encoded by an alt (abundant larval transcript) gene family. While well-documented in L3 larvae of other filariae species, this gene family had not been explored in dirofilariasis. The research involved cloning Dr20/22 cDNA, molecular characterization, and evaluating its potential application in the diagnosis of dirofilariasis. Although Real-Time analysis revealed mRNA expression in both adult worms and microfilariae, the native protein remained undetected in lysates from both developmental stages. This suggests the protein's specificity for L3 larvae and may be related to a process called SLTS (spliced leader trans-splicing), contributing to stage-specific gene expression. The specificity of the antigen for invasive larvae positions it as a promising early marker for dirofilariasis. However, ELISA tests using sera from infected and uninfected dogs indicated limited diagnostic utility. While further research is required, our findings contribute to a deeper understanding of the molecular and immunological aspects of host-parasite interactions and could offer insights into the parasite's strategies for evading the immune system.
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Affiliation(s)
- Mateusz Pękacz
- Division of Parasitology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, 02-786, Warsaw, Poland
| | - Katarzyna Basałaj
- Museum and Institute of Zoology, Polish Academy of Sciences, 00-818, Warsaw, Poland
| | - Daniel Młocicki
- Department of General Biology and Parasitology, Medical University of Warsaw, 02-004, Warsaw, Poland
| | - Maciej Kamaszewski
- Department of Ichthyology and Biotechnology in Aquaculture, Institute of Animal Sciences, Warsaw University of Life Sciences-SGGW, 02-786, Warsaw, Poland
| | - Elena Carretón
- Internal Medicine, Faculty of Veterinary Medicine, University of Las Palmas de Gran Canaria, Campus Arucas, Arucas, 35413, Las Palmas, Spain
| | - Rodrigo Morchón
- Zoonotic Diseases and One Health Group, Faculty of Pharmacy, University of Salamanca, Campus Miguel Unamuno, 37007, Salamanca, Spain
| | - Marcin Wiśniewski
- Division of Parasitology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences-SGGW, 02-786, Warsaw, Poland
| | - Anna Zawistowska-Deniziak
- Department of Immunology, Institute of Functional Biology and Ecology, Faculty of Biology, University of Warsaw, 02-095, Warsaw, Poland.
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Zhan B, Bottazzi ME, Hotez PJ, Lustigman S. Advancing a Human Onchocerciasis Vaccine From Antigen Discovery to Efficacy Studies Against Natural Infection of Cattle With Onchocerca ochengi. Front Cell Infect Microbiol 2022; 12:869039. [PMID: 35444961 PMCID: PMC9015098 DOI: 10.3389/fcimb.2022.869039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/07/2022] [Indexed: 11/19/2022] Open
Abstract
Human onchocerciasis is a devastating neglected tropical disease caused by infection of the filarial nematode Onchocerca volvulus. The infection can cause irreversible visual impairment or blindness and stigmatizing dermatitis. More than 32 million people were estimated to be infected with O. volvulus in Africa, and 385,000 suffered from blindness. Even though the implementation of mass drug administration (MDA) with ivermectin has reduced the global prevalence of onchocerciasis, O. volvulus infection remains challenging to control because MDA with ivermectin cannot be implemented in endemic areas co-endemic with loiasis due to the risk of severe adverse events. There is also emerging drug resistance to ivermectin that further complicates the elimination of onchocerciasis. Thus, the development of a vaccine that would induce protective immunity and reduce infection burden is essential. Efforts to develop prophylactic and/or therapeutic vaccines for onchocerciasis have been explored since the late 1980s by many researchers and entities, and here we summarize the recent advances made in the development of vaccines against the infection of O. volvulus and onchocerciasis.
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Affiliation(s)
- Bin Zhan
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX, United States
| | - Maria Elena Bottazzi
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX, United States
| | - Peter J. Hotez
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX, United States
| | - Sara Lustigman
- Laboratory of Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY, United States
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Carithers DS. Examining the role of macrolides and host immunity in combatting filarial parasites. Parasit Vectors 2017; 10:182. [PMID: 28410595 PMCID: PMC5391593 DOI: 10.1186/s13071-017-2116-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 03/28/2017] [Indexed: 11/10/2022] Open
Abstract
Macrocyclic lactones (MLs), specifically the avermectins and milbemycins, are known for their effectiveness against a broad spectrum of disease-causing nematodes and arthropods in humans and animals. In most nematodes, drugs in this class induce paralysis, resulting in starvation, impaired ability to remain associated with their anatomical environment, and death of all life stages. Initially, this was also thought to be the ML mode of action against filarial nematodes, but researchers have not been able to validate these characteristic effects of immobilization/starvation of MLs in vitro, even at higher doses than are possible in vivo. Relatively recently, ML receptor sites exclusively located proximate to the excretory-secretory (ES) apparatus were identified in Brugia malayi microfilaria and an ML-induced suppression of secretory protein release by B. malayi microfilariae was demonstrated in vitro. It is hypothesized here that suppression of these ES proteins prevents the filarial worm from interfering with the host's complement cascade, reducing the ability of the parasite to evade the immune system. Live microfilariae and/or larvae, thus exposed, are attacked and presented to the host's innate immune mechanisms and are ultimately killed by the immune response, not the ML drug. These live, exposed filarial worms stimulate development of innate, cellular and humoral immune responses that when properly stimulated, are capable of clearing all larvae or microfilariae present in the host, regardless of their individual sensitivity to MLs. Additional research in this area can be expected to improve our understanding of the relationships among filarial worms, MLs, and the host immune system, which likely would have implications in filarial disease management in humans and animals.
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Affiliation(s)
- Doug S Carithers
- Boehringer Ingelheim, 3239 Satellite Boulevard, Duluth, GA, 30096, USA.
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Sassi AJ, Geary JF, Leroux LP, Moorhead AR, Satti M, Mackenzie CD, Geary TG. Identification ofDirofilaria immitisProteins Recognized by Antibodies from Infected Dogs. J Parasitol 2014; 100:364-7. [DOI: 10.1645/13-437.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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Morris CP, Evans H, Larsen SE, Mitre E. A comprehensive, model-based review of vaccine and repeat infection trials for filariasis. Clin Microbiol Rev 2013; 26:381-421. [PMID: 23824365 PMCID: PMC3719488 DOI: 10.1128/cmr.00002-13] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SUMMARY Filarial worms cause highly morbid diseases such as elephantiasis and river blindness. Since the 1940s, researchers have conducted vaccine trials in 27 different animal models of filariasis. Although no vaccine trial in a permissive model of filariasis has provided sterilizing immunity, great strides have been made toward developing vaccines that could block transmission, decrease pathological sequelae, or decrease susceptibility to infection. In this review, we have organized, to the best of our ability, all published filaria vaccine trials and reviewed them in the context of the animal models used. Additionally, we provide information on the life cycle, disease phenotype, concomitant immunity, and natural immunity during primary and secondary infections for 24 different filaria models.
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Affiliation(s)
- C. Paul Morris
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Holly Evans
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Sasha E. Larsen
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Edward Mitre
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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6
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Abstract
Heartworm disease due to Dirofilaria immitis continues to cause severe disease and even death in dogs and other animals in many parts of the world, even though safe, highly effective and convenient preventatives have been available for the past two decades. Moreover, the parasite and vector mosquitoes continue to spread into areas where they have not been reported previously. Heartworm societies have been established in the USA and Japan and the First European Dirofilaria Days (FEDD) Conference was held in Zagreb, Croatia, in February of 2007. These organizations promote awareness, encourage research and provide updated guidelines for the diagnosis, treatment and prevention of heartworm disease. The chapter begins with a review of the biology and life cycle of the parasite. It continues with the prevalence and distribution of the disease in domestic and wild animals, with emphasis on more recent data on the spreading of the disease and the use of molecular biology techniques in vector studies. The section on pathogenesis and immunology also includes a discussion of the current knowledge of the potential role of the Wolbachia endosymbiont in inflammatory and immune responses to D. immitis infection, diagnostic use of specific immune responses to the bacteria, immunomodulatory activity and antibiotic treatment of infected animals. Canine, feline and ferret heartworm disease are updated with regard to the clinical presentation, diagnosis, prevention, therapy and management of the disease, with special emphasis on the recently described Heartworm Associated Respiratory Disease (HARD) Syndrome in cats. The section devoted to heartworm infection in humans also includes notes on other epizootic filariae, particularly D. repens in humans in Europe. The chapter concludes with a discussion on emerging strategies in heartworm treatment and control, highlighting the potential role of tetracycline antibiotics in adulticidal therapy.
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Anand SB, Gnanasekar M, Thangadurai M, Prabhu PR, Kaliraj P, Ramaswamy K. Immune response studies with Wuchereria bancrofti vespid allergen homologue (WbVAH) in human lymphatic filariasis. Parasitol Res 2007; 101:981-8. [PMID: 17558521 PMCID: PMC2763210 DOI: 10.1007/s00436-007-0571-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Accepted: 04/26/2007] [Indexed: 10/23/2022]
Abstract
A homologue of Brugia malayi venom allergen (BmVAH) was cloned from the infective stages (L3) of Wuchereria bancrofti. Sequence analysis showed 90% sequence identity between WbVAH and BmVAH. Recombinant WbVAH was then expressed and purified. VAH from other nematode parasites is being evaluated as potential vaccine candidates. Because W. bancrofti infections are more prevalent than B. malayi, it will significantly benefit using W. bancrofti antigens for vaccine development. In this study, we have evaluated the human immune responses to rWbVAH in putatively immune individuals who live in the endemic regions (endemic normal, EN) to determine the vaccine potential of WbVAH. These responses were then compared to those in infected individuals (microfilaraemic, MF and chronic pathology, CP). Results show that EN subjects carry WbVAH-specific IgG1, IgG2, and IgG3 circulating antibodies. It is interesting to note that CP patients also carried antibodies against WbVAH that was mainly of the IgG3 isotype. Peripheral blood mononuclear cells (PBMC) from EN individuals responded strongly to rWbVAH by proliferating and secreting IFN-gamma. PBMC from MF patients also proliferated in response to rWbVAH but secreted mainly IL-10. Thus, there was a clear dichotomy in the cytokine production by infected patients vs individuals who are putatively immune (EN). Although vaccine potential of WbVAH has not been established yet, our findings suggest that WbVAH mediated immune responses in EN individuals is primarily Th1-biased. Further vaccination studies are underway in animal models to determine the role of WbVAH in protective immunity against W. bancrofti and B. malayi infections.
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Hayasaki M, Mori N, Hongo H, Katsuya A, Song KH, Une S, Ikeda T, Ooi HK, Uchida A. Immunoblot analysis of specific antigen bands predictable for Dirofilaria immitis infection in cats. Vet Parasitol 2005; 131:325-9. [PMID: 15964689 DOI: 10.1016/j.vetpar.2005.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Revised: 04/15/2005] [Accepted: 05/03/2005] [Indexed: 11/26/2022]
Abstract
Serial sera from four mongrel cats experimentally inoculated with infectious larvae of Dirofilaria immitis were analyzed by immunoblot patterns against a phosphate buffered saline-extract of D. immitis. Antigen-specific protein bands detected indicate that the low molecular weight bands of 36, 32, 22, 19 and 14 kDa, are predictable for positive adult worm infection, suggesting diagnostic usefulness for adult D. immitis infection in cats.
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Affiliation(s)
- Mineo Hayasaki
- Veterinary Clinical Center, School of Veterinary Medicine, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan.
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Wu Y, Egerton G, Pappin DJC, Harrison RA, Wilkinson MC, Underwood A, Bianco AE. The Secreted Larval Acidic Proteins (SLAPs) of Onchocerca spp. are encoded by orthologues of the alt gene family of Brugia malayi and have host protective potential. Mol Biochem Parasitol 2004; 134:213-24. [PMID: 15003841 DOI: 10.1016/j.molbiopara.2003.12.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Accepted: 12/03/2003] [Indexed: 10/26/2022]
Abstract
Onchocerca volvulus is a tissue-dwelling, vector-borne nematode parasite of humans and the causative agent of onchocerciasis, or 'River Blindness'. Resistance to infection is associated with immune responses to the infective, third-stage (L3) larvae. The antigens of greatest interest for their vaccine potential are surface and secreted molecules. We have previously identified a family of Secreted Larval Acidic Proteins (SLAPs) from the L3 larvae of O. volvulus by biosynthetic labelling. Here, we provide further characterisation of these molecules following cloning and expression of the corresponding cDNAs. Using protein sequencing, we show that SLAPs are members of the alt gene family, first described in the lymphatic filarial parasite, Brugia malayi. Ov-ALT-1 and Ov-ALT-2 correspond with 20 and 18kDa SLAPs. Both proteins are highly acidic and related by sequence, differing chiefly in an 8-amino acid deletion from Ov-ALT-2. By immunochemistry, we confirm that Ov-ALTs are highly stage-specific, being expressed exclusively in late L2 and L3 larvae during growth in the vector. They are synthesised and stored in the glandular oesophagus. Secretion is triggered by the resumption of development in the definitive host and occurs via the pseudocoelom and cuticle. Serological responses in humans to recombinant Ov-ALT-1 indicate that the level of IgG production may be governed by the force of transmission but does not overtly reflect infection status. Immunisation of mice with recombinant Ov-ALT-1 resulted in a modest level of protection against challenge with O. volvulus L3 larvae (P = 0.036). We conclude that Ov-ALT genes, like those of other filariae, are of interest from the standpoint of parasite transmission and infectivity. They may also offer promise as components of a future sub-unit vaccine should the means to enhance protection be achieved.
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Affiliation(s)
- Yang Wu
- Division of Molecular Biology and Immunology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK.
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10
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Prieto G, Ceciliani F, Venco L, Morchón R, Simón F. Feline dirofilariosis: antibody response to antigenic fractions containing specific 20 to 30 kDa polypeptides from the adult Dirofilaria immitis somatic antigen. Vet Parasitol 2002; 103:341-53. [PMID: 11777613 DOI: 10.1016/s0304-4017(01)00540-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Fractions from the adult somatic antigen (SA) Dirofilaria immitis complex, containing polypeptides from 20 to 30kDa, previously identified as molecular markers of feline dirofilariosis are isolated by sequential application of gel filtration and anion exchange chromatography. Indirect enzyme-linked immunosorbent assays, employing these fractions (20-26kDa/ELISAF1 and 30kDa/ELISAF7) show multivalent diagnostic capacities: they were able to detect pre-patent infections 2 months after infection, infections in clinical phase, and the fall of antibodies after the worms were removed from the heart, or the application of a ivermectin treatment. The results obtained by the two tests correlated well, in spite of the fact that ELISAF1 was most useful to detect antibodies in sera from cats in the clinical phase, while ELISAF7 has more sensitivity for the early detection of the infections. Both ELISAs were useful in the detection of the decrease of antibodies after the worms were removed by surgery or pharmacological treatment.
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Affiliation(s)
- G Prieto
- Laboratorio de Parasitología, Facultad de Farmacia, Universidad de Salamanca, Avda., Campo Charro s/n, 37007 Salamanca, Spain
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11
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Maizels RM, Gomez-Escobar N, Gregory WF, Murray J, Zang X. Immune evasion genes from filarial nematodes. Int J Parasitol 2001; 31:889-98. [PMID: 11406138 DOI: 10.1016/s0020-7519(01)00213-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Helminth parasites have large genomes (approximately 10(8) bp) which are likely to encode a spectrum of products able to block or divert the host immune response. We have employed three parallel approaches to identify the first generation of 'immune evasion genes' from parasites such as the filarial nematode Brugia malayi. The first strategy is a conventional route to characterise prominent surface or secreted antigens. In this way we have identified a 15-kDa protein, which is located on the surface of both L3 and adult B. malayi, and secreted by these parasites in vitro, as a member of the cystatin (cysteine protease inhibitor) family. This product, Bm-CPI-2, blocks conventional cysteine proteases such as papain, but also the aspariginyl endopeptidase involved in the Class II antigen processing pathway in human B cells. In parallel, we identified the major T cell-stimulating antigen from the microfilarial stage as a serpin (serine protease inhibitor), Bm-SPN-2. Microfilariae secrete this product which blocks two key proteases of the neutrophil, a key mediator of inflammation and innate immunity. The second route involves a priori hypotheses that helminth parasites encode homologues of mammalian cytokines such as TGF-beta which are members of broad, ancient metazoan gene families. We have identified two TGF-beta homologues in B. malayi, and shown that one form (Bm-TGH-2) is both secreted by adult parasites in vitro and able to bind to host TGF-beta receptors. Likewise, B. malayi expresses homologues of mammalian MIF, which are remarkably similar in both structure and function to the host protein, even though amino acid identity is only 28%. Finally, we deployed a third method of selecting critical genes, using an expression-based criterion to select abundant mRNAs taken from key points in parasite life histories. By this means, we have shown that the major transcript present in mosquito-borne infective larvae, Bm-ALT, is a credible vaccine candidate for use against lymphatic filariasis, while a second abundantly-expressed gene, Bm-VAL-1, is similar to a likely vaccine antigen being developed against hookworm parasites.
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Affiliation(s)
- R M Maizels
- Institute of Cell, Animal and Population Biology, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK.
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12
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Tang L, Frank G. Identification and characterization of an aromatic amino acid decarboxylase from the filarial nematode, Dirofilaria immitis. Biol Chem 2001; 382:115-22. [PMID: 11258661 DOI: 10.1515/bc.2001.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A novel secreted aromatic amino acid decarboxylase-like molecule was identified in the excretory/secretory products of L3/L4 larvae as well as in an extract of adult Dirofilaria immitis. The secretion of the enzyme was developmentally regulated. Peak enzyme activities were detected in the culture medium before and after the molting of L3 larvae in vitro. The enzyme was purified from D. immitis adult extracts and the excretory/secretory products of L3/L4 larvae using different chromatographic methods followed by isoelectric focusing and SDS-PAGE. The enzyme has a molecular mass of 48 kDa and a pI of 5.6, and shows a specific enzymatic activity towards the aromatic amino acid substrates phenylalanine, tyrosine and tryptophan. The enzyme's activity did not show an absolute requirement for exogenous pyridoxal-5-phosphate. However, addition of pyridoxal-5-phosphate at 5 microM in the reaction increased the enzyme activity greatly. The enzyme had the ability to catalyze the formation of dopamine from L-dopa. Studies on the effects of inhibitors on the enzyme activity showed that the enzyme was sensitive to Pefabloc and p-chloromercuribenzoic acid, but not to diisopropyl flurophosphate. The Km values of the enzyme for H-Phe-AMC, H-Tyr-AMC and H-Trp-AMC were calculated to be 32.1 microM, 35.1 microM and 29.1 microM, respectively.
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Affiliation(s)
- L Tang
- Heska Corporation, Fort Collins, Colorado 80525, USA
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13
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Abraham D, Leon O, Leon S, Lustigman S. Development of a recombinant antigen vaccine against infection with the filarial worm Onchocerca volvulus. Infect Immun 2001; 69:262-70. [PMID: 11119514 PMCID: PMC97880 DOI: 10.1128/iai.69.1.262-270.2001] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Efforts to control Onchocerca volvulus, the etiologic agent of river blindness, have been limited to vector control and drug treatment to eliminate microfilariae, with no means available to prevent infection. The goal of this study was to develop a vaccine against this infection using recombinant antigens that are expressed in the early larval stages of the parasite. Five recombinant antigens, Ov7, Ov64, OvB8, Ov9M, and Ov73k, were identified by screening adult and larval cDNA libraries with antibodies from immune humans, chimpanzees, or rabbits. When mice were immunized with the five individual recombinant antigens, statistically significant reductions in parasite survival were induced in mice immunized with Ov7, OvB8, or Ov64, when administered in alum but not when injected in Freund's complete adjuvant (FCA). Live larvae recovered from control and immunized mice were analyzed to determine their developmental stages. A decrease in the percentage of larvae molting from the third stage to the fourth stage was observed with mice immunized with Ov7, Ov64, or OvB8 in alum but not with mice immunized with Ov9 and Ov73k or with mice immunized with any of the five antigens in FCA. Mice immunized with a cocktail of the three protective antigens developed protective immunity equal to that seen with mice immunized with individual antigens. This study has identified, for the first time, three recombinant antigens capable of inducing protective immunity to O. volvulus. Furthermore, since the antigens functioned with alum as the adjuvant, this vaccine could potentially be used clinically to prevent river blindness in humans.
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Affiliation(s)
- D Abraham
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
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14
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Allen JE, Daub J, Guiliano D, McDonnell A, Lizotte-Waniewski M, Taylor DW, Blaxter M. Analysis of genes expressed at the infective larval stage validates utility of Litomosoides sigmodontis as a murine model for filarial vaccine development. Infect Immun 2000; 68:5454-8. [PMID: 10948183 PMCID: PMC101817 DOI: 10.1128/iai.68.9.5454-5458.2000] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We used an expressed sequence tag approach to analyze genes expressed by the infective larvae of the rodent filarial parasite Litomosoides sigmodontis. One hundred fifty two new genes were identified, including several proposed as vaccine candidates in studies with human filarial parasites. Our findings have important implications for the use of L. sigmodontis as a model for filarial infection.
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Affiliation(s)
- J E Allen
- Institute of Cell, Animal, and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, United Kingdom
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15
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Gregory WF, Atmadja AK, Allen JE, Maizels RM. The abundant larval transcript-1 and -2 genes of Brugia malayi encode stage-specific candidate vaccine antigens for filariasis. Infect Immun 2000; 68:4174-9. [PMID: 10858234 PMCID: PMC101719 DOI: 10.1128/iai.68.7.4174-4179.2000] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lymphatic filariasis is a major tropical disease caused by the mosquito-borne nematodes Brugia and Wuchereria. About 120 million people are infected and at risk of lymphatic pathology such as acute lymphangitis and elephantiasis. Vaccines against filariasis must generate immunity to the infective mosquito-derived third-stage larva (L3) without accentuating immunopathogenic responses to lymphatic-dwelling adult parasites. We have identified two highly expressed genes, designated abundant larval transcript-1 and -2 (alt-1 and alt-2), from each of which mRNAs account for >1% of L3 cDNAs. ALT-1 and ALT-2 share 79% amino acid identity across 125 residues, including a putative signal sequence and a prominent acidic tract. Expression of alt-1 and alt-2 is initiated midway through development in the mosquito, peaking in the infective larva and declining sharply following entry into the host. Humans exposed to Brugia malayi show a high frequency of immunoglobulin G1 (IgG1) and IgG3 antibodies to ALT-1 and -2, distinguishing them from adult-stage antigens, which are targeted by the IgG4 isotype. Immunization of susceptible rodents (jirds) with ALT-1 elicited a 76% reduction in parasite survival, the highest reported for a single antigen from any filarial parasite. ALT-1 and the closely related ALT-2 are therefore strong candidates for a future vaccine against human filariasis.
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Affiliation(s)
- W F Gregory
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh, United Kingdom
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16
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Pogonka T, Oberländer U, Marti T, Lucius R. Acanthocheilonema viteae: characterization of a molt-associated excretory/secretory 18-kDa protein. Exp Parasitol 1999; 93:73-81. [PMID: 10502469 DOI: 10.1006/expr.1999.4445] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Post-invasive third-stage larvae (pL3) of Acanthocheilonema viteae were labeled with [(35)S]-methionine in vivo, and proteins released into the culture supernatant before and during the third molt were analyzed. The molting supernatant (MSN) contained abundant proteins of 14, 18, 29, and 36 kDa. The 14- and 29-kDa proteins were exclusively found in the MSN, while the 18- and 36-kDa proteins were also produced by nonmolting pL3, albeit in much lower quantities. The cDNA for the most abundant protein in the MSN, an 18-kDa protein (Av18), was isolated by polymerase chain reaction (PCR) with reverse transcribed (RT) RNA of pL3, using information of the protein sequence. The Av18 full-length cDNA of 583 base pairs contained the 5' spliced leader sequence of nematodes, an open reading frame of 427 base pairs, and a poly(A) tail in typical distance to a polyadenylation signal. The deduced amino acid sequence encodes for a protein with a calculated size of 15.8 kDa. The N-terminus starts with a hydrophobic signal sequence and a predicted cleavage site after amino acid 20. The Av18 protein showed homologies to the deduced amino acid sequence of the larval transcripts Bm-alt-1 and alt-2 of Brugia malayi and to the Dirofilaria immitis proteins Di20/22 as well as to the Onchocerca volvulus proteins Ov-alt-1 and Ov-alt-2. Av18 is present in all parasite stages within the mammalian host, as determined by immunoblot with sera against the Escherichia coli-expressed protein and RT-PCR experiments. However, it was released into culture medium only by L3 and adult female worms. In female worms Av18 was localized in the cuticular region as demonstrated by immunofluorescent antibody tests using cryosections.
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Affiliation(s)
- T Pogonka
- Department of Molecular Parasitology (Institute of Biology), Humboldt University Berlin, Philippstrasse 13, Berlin, 10115, USA
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Muro A, Genchi C, Cordero M, Simón F. Human dirofilariasis in the European Union. PARASITOLOGY TODAY (PERSONAL ED.) 1999; 15:386-9. [PMID: 10461169 DOI: 10.1016/s0169-4758(99)01496-9] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The dog parasites Dirofilaria immitis and D. (Nochtiella) repens, well known as zoonotic agents, are widely distributed in southern Europe. Although both species are canine parasites, infection with immature worms has been found in humans, who develop nodules, mainly in subcutaneous tissue or in lung parenchyma arising from branches of the pulmonary artery. In humans, the parasites do not usually reach the adult stage and microfilaremia is absent, as has been shown by diagnosis using invasive methods for removing the nodules. In this article, Antonio Muro, Claudio Genchi, Miguel Cordero and Fernando Simón review the current situation concerning the clinical and epidemiological aspects, immune response and diagnosis of human dirofilariases.
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Affiliation(s)
- A Muro
- Laboratorio de Parasitolog a, Facultad de Farmacia, Universidad de Salamanca, Spain
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Frank GR, Wisnewski N, Brandt KS, Carter CR, Jennings NS, Selkirk ME. Molecular cloning of the 22-24 kDa excretory-secretory 22U protein of Dirofilaria immitis and other filarial nematode parasites. Mol Biochem Parasitol 1999; 98:297-302. [PMID: 10080399 DOI: 10.1016/s0166-6851(98)00173-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- G R Frank
- Heska Corporation, Fort Collins, CO 80525, USA.
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19
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Joseph GT, Huima T, Lustigman S. Characterization of an Onchocerca volvulus L3-specific larval antigen, Ov-ALT-1. Mol Biochem Parasitol 1998; 96:177-83. [PMID: 9851616 DOI: 10.1016/s0166-6851(98)00094-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- G T Joseph
- Laboratory of Virology and Parasitology, The Lindsley F. Kimball Research Institute, New York Blood Center, NY, USA
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20
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Gregory WF, Blaxter ML, Maizels RM. Differentially expressed, abundant trans-spliced cDNAs from larval Brugia malayi. Mol Biochem Parasitol 1997; 87:85-95. [PMID: 9233676 DOI: 10.1016/s0166-6851(97)00050-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Isolation and cloning of abundant reverse transcriptase-polymerase chain reaction (RT-PCR) products from the filarial nematode Brugia malayi using the conserved nematode spliced leader sequence and poly A as amplification targets has allowed us to identify abundant, stage specific transcripts from infective and post-infective larvae. The predicted protein products of the most prominent full-length transcripts from mosquito-derived L3 parasites are: (i) Bm-ALT-1, a homologue of a Dirofilaria immitis abundant larval protein: (ii) Bm-CPI-1, a cystatin-type cysteine protease inhibitor; (iii) Bm-ALT-3, a novel predicted 6 kDa glycine/tyrosine-rich protein; and (iv) Bm-TPH-1, a homologue of a mammalian translationally-controlled tumour protein. Some transcripts were not full-length but had mis-primed at A-rich stretches of coding sequence: the most abundant of these was Bm-col-3, a which encodes a collagen homologous to Bp-COL-1 of Brugia pahangi. Similar analysis of abundant spliced leader (SL)/oligo-dT products from fourth-stage larvae 9 days post-infection yielded two dominant transcripts: (i) Bm-cdd-1, which encodes a protein with homology to cytidine deaminase, differing at only one amino acid position from its homologue described in Brugia pahangi; and (ii) the same truncated form of Bm-col-3 found in L3 preparations. Expression of the major transcripts was assessed by PCR amplification of cDNA libraries derived from each stage of the life cycle. alt1, alt-3 and cpi-1 were all found to be specific to the L3 stage, while cdd-1 was found only in the L4 cDNA library. Expression of these larval-specific transcripts was not detected in either microfilarial or adult libraries.
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Affiliation(s)
- W F Gregory
- Institute of Cell, Animal and Population Biology, Ashworth Laboratories University of Edinburgh, UK
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Frank GR, Tripp CA, Grieve RB. Molecular cloning of a developmentally regulated protein isolated from excretory-secretory products of larval Dirofilaria immitis. Mol Biochem Parasitol 1996; 75:231-40. [PMID: 8992321 DOI: 10.1016/0166-6851(95)02534-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Three proteins isolated from the excretory-secretory products (ES) of larval Dirofilaria immitis have been previously characterized and termed the 20, 22L and 22U kDa proteins. Two of the proteins (20 and 22L) were produced and released around the time of the third molt and were specifically recognized by immune dog sera. An amino acid sequence common to both proteins was used to synthesize a DNA probe to molecularly clone these molecules from a 48-h third stage larval cDNA library. The DNA sequence of the isolated clones encoded a 17.5 kDa protein with a 21 amino acid hydrophobic leader sequence that when removed yielded a 15.3 kDa protein starting with the N-terminal sequence obtained from the 20 kDa protein and containing all sequences obtained from tryptic peptides of the 20 and 22L kDa proteins. It was hypothesized that the 20 and 22L kDa proteins were the same, differing only by a 21 amino acid hydrophobic leader sequence which was later cleaved. The calculated molecular masses were consistent with those determined by reducing Tris-tricine SDS-PAGE. Expression of the protein without the leader sequence was accomplished in Escherichia coli. Antiserum raised against the expressed protein demonstrated the presence of the protein in L3 and L4, but not in adults or microfilariae. Expression of the protein with the leader sequence using a baculovirus system demonstrated processing of the signal sequence at the same time as found in larval D. immitis ES. Sera from dogs immune to infection were reactive with the D. immitis proteins expressed in either E. coli or insect cells.
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Affiliation(s)
- G R Frank
- Paravax, Inc., Fort Collins, CO 80525, USA.
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