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Li X, Yin J, Wang D, Gao X, Zhang Y, Wu M, Zhu G. The mucin-like, secretory type-I transmembrane glycoprotein GP900 in the apicomplexan Cryptosporidium parvum is cleaved in the secretory pathway and likely plays a lubrication role. Parasit Vectors 2022; 15:170. [PMID: 35581607 PMCID: PMC9111948 DOI: 10.1186/s13071-022-05286-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 04/13/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cryptosporidium parvum is a zoonotic parasite and member of the phylum Apicomplexa with unique secretory organelles, including a rhoptry, micronemes and dense granules that discharge their contents during parasite invasion. The mucin-like glycoprotein GP900 with a single transmembrane domain is an immunodominant antigen and micronemal protein. It is relocated to the surface of excysted sporozoites and shed to form trails by sporozoites exhibiting gliding motility (gliding sporozoites). However, the biological process underlying its relocation and shedding remains unclear. The primary aim of this study was to determine whether GP900 is present as a transmembrane protein anchored to the plasma membrane on the surface of sporozoites and whether it is cleaved before being shed from the sporozoites. METHODS Two anti-GP900 antibodies, a mouse monoclonal antibody (mAb) to the long N-terminal domain (GP900-N) and a rabbit polyclonal antibody (pAb) to the short C-terminal domain (GP900-C), were produced for the detection of intact and cleaved GP900 proteins in sporozoites and other parasite developmental stages by microscopic immunofluorescence assay and in discharged molecules by enzyme-linked immunosorbent assay. RESULTS Both anti-GP900 antibodies recognized the apical region of unexcysted and excysted sporozoites. However, anti-GP900-N (but not anti-GP900-C) also stained both the pellicles/surface of excysted sporozoites and the trails of gliding sporozoites. Both antibodies stained the intracellular meronts, both developing and developed, but not the macro- and microgamonts. Additionally, the epitope was recognized by anti-GP900-N (but not anti-GP900-C) and detected in the secretions of excysted sporozoites and intracellular parasites. CONCLUSIONS GP900 is present in sporozoites and intracellular meronts, but absent in sexual stages. It is stored in the micronemes of sporozoites, but enters the secretory pathway during excystation and invasion. The short cytoplasmic domain of GP900 is cleaved in the secretory pathway before it reaches the extracellular space. The molecular features and behavior of GP900 imply that it plays mainly a lubrication role.
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Affiliation(s)
- Xiaohui Li
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, The College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Jigang Yin
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, The College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Dongqiang Wang
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, The College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Xin Gao
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, The College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Ying Zhang
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, The College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Mingbo Wu
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, The College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Guan Zhu
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, The College of Veterinary Medicine, Jilin University, Changchun, 130062, China.
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Gao X, Yin J, Wang D, Li X, Zhang Y, Wang C, Zhang Y, Zhu G. Discovery of New Microneme Proteins in Cryptosporidium parvum and Implication of the Roles of a Rhomboid Membrane Protein (CpROM1) in Host-Parasite Interaction. Front Vet Sci 2021; 8:778560. [PMID: 34966810 PMCID: PMC8710574 DOI: 10.3389/fvets.2021.778560] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 11/12/2021] [Indexed: 01/25/2023] Open
Abstract
Apicomplexan parasites possess several unique secretory organelles, including rhoptries, micronemes, and dense granules, which play critical roles in the invasion of host cells. The molecular content of these organelles and their biological roles have been well-studied in Toxoplasma and Plasmodium, but are underappreciated in Cryptosporidium, which contains many parasites of medical and veterinary importance. Only four proteins have previously been identified or proposed to be located in micronemes, one of which, GP900, was confirmed using immunogold electron microscopy (IEM) to be present in the micronemes of intracellular merozoites. Here, we report on the discovery of four new microneme proteins (MICs) in the sporozoites of the zoonotic species C. parvum, identified using immunofluorescence assay (IFA). These proteins are encoded by cgd3_980, cgd1_3550, cgd1_3680, and cgd2_1590. The presence of the protein encoded by cgd3_980 in sporozoite micronemes was further confirmed using IEM. Cgd3_980 encodes one of the three C. parvum rhomboid peptidases (ROMs) and is, thus, designated CpROM1. IEM also confirmed the presence of CpROM1 in the micronemes of intracellular merozoites, parasitophorous vacuole membranes (PVM), and feeder organelles (FO). CpROM1 was enriched in the pellicles and concentrated at the host cell–parasite interface during the invasion of sporozoites and its subsequent transformation into trophozoites. CpROM1 transcript levels were also higher in oocysts and excysted sporozoites than in the intracellular parasite stages. These observations indicate that CpROM1, an intramembrane peptidase with membrane proteolytic activity, is involved in host–parasite interactions, including invasion and proteostasis of PVM and FO.
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Affiliation(s)
- Xin Gao
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, and the College of Veterinary Medicine, Jilin University, Changchun, China
| | - Jigang Yin
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, and the College of Veterinary Medicine, Jilin University, Changchun, China
| | - Dongqiang Wang
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, and the College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xiaohui Li
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, and the College of Veterinary Medicine, Jilin University, Changchun, China
| | - Ying Zhang
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, and the College of Veterinary Medicine, Jilin University, Changchun, China
| | - Chenchen Wang
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, and the College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yuanyuan Zhang
- Electron Microscopy Core Facility, The Institute of Zoonosis, Jilin University, Changchun, China
| | - Guan Zhu
- Key Laboratory of Zoonosis Research of the Ministry of Education, The Institute of Zoonosis, and the College of Veterinary Medicine, Jilin University, Changchun, China
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Avendaño C, Jenkins M, Méndez-Callejas G, Oviedo J, Guzmán F, Patarroyo MA, Sánchez-Acedo C, Quílez J. Cryptosporidium spp. CP15 and CSL protein-derived synthetic peptides' immunogenicity and in vitro seroneutralisation capability. Vaccine 2018; 36:6703-6710. [PMID: 30268732 DOI: 10.1016/j.vaccine.2018.09.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 09/11/2018] [Accepted: 09/20/2018] [Indexed: 12/12/2022]
Abstract
Cryptosporidium spp. is a zoonotic intracellular protozoan and a significant cause of diarrhoea in humans and animals worldwide. This parasite can cause high morbidity in immunocompromised people and children in developing countries, livestock being the main reservoir. This study was aimed at performing preliminary tests on Swiss albino weaned mice (ICR) to evaluate the humoral immune response induced against peptides derived from Cryptosporidium parvum CP15 (15 kDa sporozoite surface antigen) and CSL (circumsporozoite-like antigen) proteins. Peptides were identified and characterised using bioinformatics tools and were chemically synthesised. The antibody response was determined and the neutralising effect of antibodies was measured in cell culture. Despite all peptides studied here were capable of stimulating antibody production, neutralising antibodies were detected for just two of the CP15-derived ones. Additional studies aimed at evaluating further the potential of such peptides as vaccine candidates are thus recommended.
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Affiliation(s)
- Catalina Avendaño
- Universidad de Ciencias Aplicadas y Ambientales U.D.C.A, Animal Sciences Faculty, Bogotá D.C., Colombia.
| | - Mark Jenkins
- Agricultural Research Service (ARS), USDA, Animal Parasitic Diseases Laboratory, Beltsville, USA
| | - Gina Méndez-Callejas
- Universidad de Ciencias Aplicadas y Ambientales U.D.C.A, Health Sciences Faculty, Bogotá D.C., Colombia
| | | | - Fanny Guzmán
- Pontificia Universidad Católica de Valparaiso, Núcleo de Biotecnología de Curauma (NBC), Valparaiso, Chile
| | - Manuel A Patarroyo
- Fundación Instituto de Inmunología de Colombia (FIDIC), Molecular Biology and Immunology Department, Bogotá D.C., Colombia; Universidad del Rosario, School of Medicine and Health Sciences, Bogotá D.C., Colombia
| | - Caridad Sánchez-Acedo
- University of Zaragoza, Animal Pathology Department, Veterinary Sciences Faculty, Spain
| | - Joaquín Quílez
- University of Zaragoza, Animal Pathology Department, Veterinary Sciences Faculty, Spain
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Loro E, Gianazza E, Cazzola S, Malena A, Wait R, Begum S, Brizio C, Dabbeni-Sala F, Vergani L. Development and characterization of polyspecific anti-mitochondrion antibodies for proteomics studies on in toto tissue homogenates. Electrophoresis 2009; 30:1329-41. [PMID: 19382133 DOI: 10.1002/elps.200800576] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We describe the characterization of polyclonal antibodies directed against the whole mitochondrial subproteome, as obtained by hyperimmunization of rabbits with an organelle fraction purified from human skeletal muscle and lysed by sonication. After 2-DE separations with either blue native electrophoresis or IPG as first dimension and blotting, the polyspecific antibodies detect 113 proteins in human muscle mitochondria, representative of all major biochemical pathways and oxidative phosphorylation (OXPHOS) complexes, and cross-react with 28 proteins in rat heart mitochondria. Using as sample cryosections of human muscle biopsies lysed in urea/thiourea/CHAPS, the mitochondrial subproteome can be detected against the background of contractile proteins. When comparing with controls samples from mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes patients, immunoblotting shows in the latter a drastic reduction for the subunits of OXPHOS complex I as well as an increase of several enzymes, including ATP synthase. This finding is the first evidence at the proteomic level of massive up-regulation in a number of metabolic pathways by which the affected tissues try to compensate for the deficit in the OXPHOS machinery.
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Affiliation(s)
- Emanuele Loro
- Dipartimento di Neuroscienze, Facoltà di Medicina, Università degli Studi, Padova, Italy
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Boulter-Bitzer JI, Lee H, Trevors JT. Molecular targets for detection and immunotherapy in Cryptosporidium parvum. Biotechnol Adv 2006; 25:13-44. [PMID: 17055210 DOI: 10.1016/j.biotechadv.2006.08.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 08/14/2006] [Accepted: 08/22/2006] [Indexed: 11/21/2022]
Abstract
Cryptosporidium parvum is an obligate protozoan parasite responsible for the diarrheal illness cryptosporidiosis in humans and animals. Although C. parvum is particularly pathogenic in immunocompromised hosts, the molecular mechanisms by which C. parvum invades the host epithelial cells are not well understood. Characterization of molecular-based antigenic targets of C. parvum is required to improve the specificity of detection, viability assessments, and immunotherapy (treatment). A number of zoite surface (glyco)proteins are known to be expressed during, and believed to be involved in, invasion and infection of host epithelial cells. In the absence of protective treatments for this illness, antibodies targeted against these zoite surface (glyco)proteins offers a rational approach to therapy. Monoclonal, polyclonal and recombinant antibodies represent useful immunotherapeutic means of combating infection, especially when highly immunogenic C. parvum antigens are utilized as targets. Interruption of life cycle stages of this parasite via antibodies that target critical surface-exposed proteins can potentially decrease the severity of disease symptoms and subsequent re-infection of host tissues. In addition, development of vaccines to this parasite based on the same antigens may be a valuable means of preventing infection. This paper describes many of the zoite surface glycoproteins potentially involved in infection, as well as summarizes many of the immunotherapeutic studies completed to date. The identification and characterization of antibodies that bind to C. parvum-specific cell surface antigens of the oocyst and sporozoite will allow researchers to fully realize the potential of molecular-based immunotherapy to this parasite.
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Smith HV, Nichols RAB, Grimason AM. Cryptosporidium excystation and invasion: getting to the guts of the matter. Trends Parasitol 2005; 21:133-42. [PMID: 15734661 DOI: 10.1016/j.pt.2005.01.007] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cryptosporidium parvum excystation and host cell invasion have been characterized in some detail ultrastructurally. However, until recently, the biochemical and molecular basis of host-parasite interactions and parasite- and host-specific molecules involved in excystation, motility and host cell invasion have been poorly understood. This article describes our understanding of Cryptosporidium excystation and the events leading to host cell invasion, and draws from information available about these processes in other apicomplexans. Many questions remain but, once the specific mechanisms are identified, they could prove to be novel targets for drug delivery.
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Affiliation(s)
- Huw V Smith
- Scottish Parasite Diagnostic Laboratory, Stobhill Hospital, Glasgow G21 3UW, Scotland, UK.
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Webster KA. Molecular methods for the detection and classification of Cryptosporidium. ACTA ACUST UNITED AC 2005; 9:263-6. [PMID: 15463775 DOI: 10.1016/0169-4758(93)90073-o] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cryptosporidiosis is a zoonotic disease caused by a parasitic protozoan belonging to the coccidial genus Cryptosporidium. Current laboratory methods are adequate for the detection of the infection when oocysts are present in great numbers, but more-sensitive means of identification are urgently required. In a recent issue of Parasitology Today, Carolyn Petersen has presented a review of the cell biology of this parasite'. Here, Kath Webster draws attention to the various methods involved in its detection and classification.
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Affiliation(s)
- K A Webster
- Central Veterinary Laboratory, Woodham Lane, New Haw, Weybridge, UK KT 15 3NB
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8
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Matsubayashi M, Kimata I, Iseki M, Lillehoj HS, Matsuda H, Nakanishi T, Tani H, Sasai K, Baba E. Cross-reactivities with Cryptosporidium spp. by chicken monoclonal antibodies that recognize avian Eimeria spp. Vet Parasitol 2005; 128:47-57. [PMID: 15725532 DOI: 10.1016/j.vetpar.2004.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2004] [Indexed: 10/26/2022]
Abstract
In a previous study, we have developed several chicken monoclonal antibodies (mAbs) against Eimeria acervulina (EA) in order to identify potential ligand molecules of Eimeria. One of these mAbs, 6D-12-G10, was found to recognize a conoid antigen of EA sporozoites and significantly inhibited the sporozoite invasions of host T lymphocytes in vitro. Furthermore, some of these chicken mAbs showed cross-reactivities with several different avian Eimeria spp. and the mAb 6D-12-G10 also demonstrated cross-reactivities with the tachyzoites of Neospora caninum and Toxoplasma gondii. Cryptosporidium spp. are coccidian parasites closely related to Eimeria spp., and especially C. parvum is an important cause of diarrhea in human and mammals. In the present study, to assess that the epitopes recognized by these chicken mAbs could exist on Cryptosporidium parasites, we examined the cross-reactivity of these mAbs with Cryptosporidium spp. using an indirect immunofluorescent assay (IFA) and Western blotting analyses. In IFA by chicken mAbs, the mAb 6D-12-G10 only showed a immunofluorescence staining at the apical end of sporozoites of C. parvum and C. muris, and merozoites of C. parvum. Western blotting analyses revealed that the mAb 6D-12-G10 reacted with the 48-kDa molecular weight band of C. parvum and C. muris oocyst antigens, 5D-11 reacted the 155 kDa of C. muris. Furthermore, these epitopes appeared to be periodate insensitive. These results indicate that the target antigen recognized by these chicken mAbs might have a shared epitope, which is present on the apical complex of apicomplexan parasites.
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Affiliation(s)
- Makoto Matsubayashi
- Department of Food and Nutrition, Osaka Joshi-Gakuen Junior College, Tennoji-ku, Osaka 543-0073, Japan
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9
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Strong WB, Gut J, Nelson RG. Cloning and sequence analysis of a highly polymorphic Cryptosporidium parvum gene encoding a 60-kilodalton glycoprotein and characterization of its 15- and 45-kilodalton zoite surface antigen products. Infect Immun 2000; 68:4117-34. [PMID: 10858229 PMCID: PMC101708 DOI: 10.1128/iai.68.7.4117-4134.2000] [Citation(s) in RCA: 265] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The apicomplexan parasite Cryptosporidium parvum is a major cause of serious diarrheal disease in both humans and animals. No efficacious chemo- or immunotherapies have been identified for cryptosporidiosis, but certain antibodies directed against zoite surface antigens and/or proteins shed by gliding zoites have been shown to neutralize infectivity in vitro and/or to passively protect against, or ameliorate, disease in vivo. We previously used monoclonal antibody 11A5 to identify a 15-kDa surface glycoprotein that was shed behind motile sporozoites and was recognized by several lectins that neutralized parasite infectivity for cultured epithelial cells. Here we report the cloning and sequence analysis of the gene encoding this 11A5 antigen. Surprisingly, the gene encoded a 330-amino-acid, mucin-like glycoprotein that was predicted to contain an N-terminal signal peptide, a homopolymeric tract of serine residues, 36 sites of O-linked glycosylation, and a hydrophobic C-terminal peptide specifying attachment of a glycosylphosphatidylinositol anchor. The single-copy gene lacked introns and was expressed during merogony to produce a 60-kDa precursor which was proteolytically cleaved to 15- and 45-kDa glycoprotein products that both localized to the surface of sporozoites and merozoites. The gp15/45/60 gene displayed a very high degree of sequence diversity among C. parvum isolates, and the numerous single-nucleotide and single-amino-acid polymorphisms defined five to six allelic classes, each characterized by additional intra-allelic sequence variation. The gp15/45/60 single-nucleotide polymorphisms will prove useful for haplotyping and fingerprinting isolates and for establishing meaningful relationships between C. parvum genotype and phenotype.
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MESH Headings
- Alleles
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Antigens, Protozoan/metabolism
- Antigens, Surface/chemistry
- Antigens, Surface/genetics
- Antigens, Surface/metabolism
- Base Sequence
- Cloning, Molecular
- Cryptosporidiosis/parasitology
- Cryptosporidium parvum/genetics
- Cryptosporidium parvum/immunology
- Cryptosporidium parvum/pathogenicity
- DNA Primers/genetics
- DNA, Protozoan/genetics
- Gene Expression Regulation, Developmental
- Genes, Protozoan
- Genotype
- Humans
- Molecular Sequence Data
- Molecular Weight
- Polymorphism, Genetic
- Protein Processing, Post-Translational
- Protozoan Proteins/chemistry
- Protozoan Proteins/genetics
- Protozoan Proteins/immunology
- Sequence Homology, Amino Acid
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Affiliation(s)
- W B Strong
- Division of Infectious Diseases, San Francisco General Hospital, University of California, San Francisco, San Francisco, California 94143-0811, USA
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10
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Abstract
Cryptosporidium parvum is an important zoonotic protozoan pathogen that causes acute infection and self-limiting gastrointestinal disease in neonatal calves. There are currently no consistently effective antimicrobials available to control cryptosporidiosis. Therefore, immunotherapeutic and vaccination protocols offer the greatest potential for long-term control of the disease. In order to devise effective control measures, it is important to better define mucosal immunity to C. parvum in young calves. This review summarizes the information that has accumulated over the last decade which helps to define the intestinal mucosal immune system in neonatal calves, and the events that occur in the intestinal mucosa after infection by C. parvum.
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Affiliation(s)
- C R Wyatt
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040, USA
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11
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Tosini F, Cacciò S, Tamburrini A, La Rosa G, Pozio E. Identification and characterisation of three antigenic proteins from Cryptosporidium parvum sporozoites using a DNA library expressing poly-histidine tagged peptides. Int J Parasitol 1999; 29:1925-33. [PMID: 10961848 DOI: 10.1016/s0020-7519(99)00158-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
To identify antigenic peptides of the parasite Cryptosporidium parvum, an expression library that allows for the production of chimeric proteins fused with a 6-histidine tag was made. The library was screened with C. parvum sporozoite rabbit anti-serum, and three positive clones (sa20, sa35, and sa40) were identified. The corresponding recombinant proteins (SA20, SA35, and SA40) were expressed in Escherichia coli and purified by metal-affinity chromatography. The sequence of sa20 and sa35 clones did not show any homology with known genes or proteins, whereas the 5' end of the sa40 clone showed homology with two previously identified C. parvum sequences. Hybridisations to intact chromosomes fractionated by pulsed-field gel electrophoresis revealed that the sa35 and sa40 sequences are localised on chromosome VII, whereas the sa20 sequence is localised on chromosome VI. Reverse transcriptase-PCR experiments showed the presence of mRNAs for sa35 and sa40 in the oocyst, whereas the sa20 mRNA was undetectable in this stage. The serological response to the three proteins was assayed in C. parvum-immunised rabbits and in immunocompetent individuals with cryptosporidiosis. The Western blot results indicated that rabbits, challenged with a sporozoite crude antigen or with an oocyst crude antigen, were highly responsive to these three antigens. Human serum samples showed a response to the three proteins, although the response to SA20 appeared to be unrelated to a recent C. parvum infection. These results suggest that the SA35 and the SA40 proteins may be useful in detecting C. parvum infections.
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Affiliation(s)
- F Tosini
- Laboratory of Parasitology, Istituto Superiore di Sanità, Rome, Italy.
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12
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Barnes DA, Bonnin A, Huang JX, Gousset L, Wu J, Gut J, Doyle P, Dubremetz JF, Ward H, Petersen C. A novel multi-domain mucin-like glycoprotein of Cryptosporidium parvum mediates invasion. Mol Biochem Parasitol 1998; 96:93-110. [PMID: 9851610 DOI: 10.1016/s0166-6851(98)00119-4] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cryptosporidium parvum is a protozoan parasite which produces self-limited disease in immunocompetent hosts and devastating, persistent diarrhea in immunocompromised individuals. There is no effective treatment for cryptosporidiosis and little is known about the basic biology of the organism. Cloning and sequence analysis of the gene encoding GP900, a previously identified > 900 kDa glycoprotein, predicts a mucin-like glycoprotein composed of distal cysteine-rich domains separated by polythreonine domains and a large membrane proximal N-glycosylated core region. A trinucleotide repeat composed predominantly of the triplet ACA encodes the threonine domains. GP900 is stored in micronemes prior to appearance on the surface of invasive forms. The concentration of native GP900 which inhibits 50% (IC50) of invasion in vitro is low picomolar; the IC50 for a recombinant cysteine rich-domain is low nanomolar. These observations indicate that GP900 is a parasite ligand for a host receptor involved in attachment/invasion and suggest that immunotherapy or chemotherapy directed against GP900 may be feasible.
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Affiliation(s)
- D A Barnes
- Department of Medicine, University of California-San Francisco General Hospital, 94110, USA
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13
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Vásquez JR, Goozé L, Kim K, Gut J, Petersen C, Nelson RG. Potential antifolate resistance determinants and genotypic variation in the bifunctional dihydrofolate reductase-thymidylate synthase gene from human and bovine isolates of Cryptosporidium parvum. Mol Biochem Parasitol 1996; 79:153-65. [PMID: 8855552 DOI: 10.1016/0166-6851(96)02647-3] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have determined the nucleic acid sequences of a gene encoding the bifunctional enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS) from bovine and human AIDS isolates of Cryptosporidium parvum. THe DHFR-TS gene was isolated from genomic DNA libraries by hybridization with a probe amplified from C. parvum genomic DNA using generic TS primers in the polymerase chain reaction. Genomic Southern and electrophoretic karyotype analyses reveal C. parvum DHFR-TS is a single-copy gene on a 1200-kb chromosome. The DHFR-TS nucleic acid sequence contains no introns and the single 1563-bp open reading frame encodes a 179 residue N-terminal DHFR domain connected by a 55 amino acid junction peptide to a 287 residue C-terminal TS domain. The sequences of the DHFR-TS gene from the bovine and human C. parvum isolates differ at two positions in the 5'-flanking sequence and at 38 positions in the encoding sequence. These DNA sequence polymorphisms will provide a powerful probe to examine the genotypic diversity and genetic population structure of C. parvum. The two sequences encode identical TS domains which share all except one of the phylogenetically conserved amino acid residues identified among reported TS sequences. The predicted DHFR domain sequences contain nine amino acid differences; these polymorphisms all map to non-active site, surface locations in known DHFR structures. The C. parvum DHFR active site contains novel residues at several positions analogous to those at which point mutations have been shown to produce antifolate resistance in other DHFRs. Thus C. parvum DHFR may be intrinsically resistant ti inhibition by some antifolate DHFR inhibitors which may explain why cryptosporidiosis is refractory to treatment with the clinically common antibacterial and antiprotozoal antifolates.
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Affiliation(s)
- J R Vásquez
- Division of Infectious Diseases, San Francisco General Hospital, CA, USA
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Steele MI, Kuhls TL, Nida K, Meka CS, Halabi IM, Mosier DA, Elliott W, Crawford DL, Greenfield RA. A Cryptosporidium parvum genomic region encoding hemolytic activity. Infect Immun 1995; 63:3840-5. [PMID: 7558289 PMCID: PMC173540 DOI: 10.1128/iai.63.10.3840-3845.1995] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Successful parasitization by Cryptosporidium parvum requires multiple disruptions in both host and protozoan cell membranes as cryptosporidial sporozoites invade intestinal epithelial cells and subsequently develop into asexual and sexual life stages. To identify cryptosporidial proteins which may play a role in these membrane alterations, hemolytic activity was used as a marker to screen a C. parvum genomic expression library. A stable hemolytic clone (H4) containing a 5.5-kb cryptosporidial genomic fragment was identified. The hemolytic activity encoded on H4 was mapped to a 1-kb region that contained a complete 690-bp open reading frame (hemA) ending in a common stop codon. A 21-kDa plasmid-encoded recombinant protein was expressed in maxicells containing H4. Subclones of H4 which contained only a portion of hemA did not induce hemolysis on blood agar or promote expression of the recombinant protein in maxicells. Reverse transcriptase-mediated PCR analysis of total RNA isolated from excysted sporozoites and the intestines of infected adult mice with severe combined immunodeficiency demonstrated that hemA is actively transcribed during the cryptosporidial life cycle.
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Affiliation(s)
- M I Steele
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City 73126, USA
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15
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Khramtsov NV, Tilley M, Blunt DS, Montelone BA, Upton SJ. Cloning and analysis of a Cryptosporidium parvum gene encoding a protein with homology to cytoplasmic form Hsp70. J Eukaryot Microbiol 1995; 42:416-22. [PMID: 7620467 DOI: 10.1111/j.1550-7408.1995.tb01605.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
An intronless gene encoding a protein of 674 amino acid residues with a molecular mass of 73,403 Da showing homology to the cytoplasmic form of the 70 kDa heat shock proteins has been cloned and sequenced from the intestinal pathogen Cryptosporidium parvum. Monospecific polyclonal antibodies obtained to recombinant protein recognized a single band with an approximate molecular mass of 70 kDa on a Western blot of C. parvum proteins, as well as the 70 kDa heat shock protein from bovine brain. Southern blot analysis suggested the gene was single copy in the C. parvum genome. Eleven perfect repeats of the sequence GGMP were found in the predicted protein near the carboxyl terminus.
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Affiliation(s)
- N V Khramtsov
- Division of Biology, Kansas State University, Manhattan 66506, USA
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Affiliation(s)
- P J O'Donoghue
- Parasitology Section, VETLAB, Department of Primary Industries, Adelaide, Australia
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17
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Wee SH, Lee CG, Kim BS, Joo HD, Kang SW. [Isolation of Cryptosporidium parvum oocysts from fecal samples--the combination of ether extraction and discontinuous sucrose gradients]. THE KOREAN JOURNAL OF PARASITOLOGY 1994; 32:7-12. [PMID: 8167112 DOI: 10.3347/kjp.1994.32.1.7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A calf and 50 mice were infected with Cryptosporidium parvum, and their fecal materials were collected and treated with ether extraction (EE), followed by discontinuous sucrose gradients (DSG) method. EE method was to remove some of fat or lipid from feces. Sediments were washed by centrifugation (1,500 x g for 10 min., 3 times) in phosphate-buffered saline and then these washed sediments were sieved sequentially through stainless steel screens with a final mesh of 250 (61 microns porosity) to remove other debris. After sieving, the materials were suspended in 2.5% potassium dichromate solution. Oocysts were counted by using a hemocytometer and the recovery rate of pure oocysts was calculated on the basis of the count. Following centrifugation (1,500 x g for 30 min.) by DSG method, most oocysts were recovered at the interface between a gravity of 1.103 and 1.064. The recovery rates of pure oocysts from the fecal suspension of the calf (3.8 x 10(7)/ml) and the mouse (3.2 x 10(6)/ml) treated with EE method were 81.6% and 51.6%, respectively. It is suggested that the recovery rate was dependent on the number of oocysts in each suspension treated with EE method. To get the 50% recovery rate, there must be more than 2 x 10(6) oocysts per ml of the fecal suspension treated with EE method. By the combination of the two methods it was possible to isolate C. parvum oocysts from normal feces of the calf and mouse as well as from diarrheic feces.
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Affiliation(s)
- S H Wee
- Veterinary Research Institute, Chonnam National University, Kwangju, Korea
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18
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Doyle PS, Crabb J, Petersen C. Anti-Cryptosporidium parvum antibodies inhibit infectivity in vitro and in vivo. Infect Immun 1993; 61:4079-84. [PMID: 8406795 PMCID: PMC281127 DOI: 10.1128/iai.61.10.4079-4084.1993] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Cryptosporidium parvum causes acute diarrhea in immunocompetent individuals and a severe life-threatening disease in immunocompromised individuals, including AIDs patients. No efficacious therapy for cryptosporidiosis has yet been reported. However, treatment of some patients with cryptosporidiosis with hyperimmune bovine colostrum has ameliorated or eliminated clinical symptoms. Consequently, it is important to identify and characterize C. parvum antigens which are the targets of protective antibodies to facilitate the development of more efficacious therapy. We report that hyperimmune bovine colostral immunoglobulin inhibits C. parvum infectivity in a reproducible in vitro assay, and we correlate this inhibition with the protective capacity of the bovine colostrum in vivo. We have also identified the major C. parvum sporozoite antigens recognized on Western blots (immunoblots) by this colostral immunoglobulin preparation. Antibodies that recognize some surface molecules of other Apicomplexan parasites are protective in vivo. Consequently, we radioiodinated membrane proteins of sporozoites and immunoprecipitated 19 molecules which are the target of immunoglobulin that is protective in vivo and in vitro.
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Affiliation(s)
- P S Doyle
- Parasitology Laboratory, San Francisco General Hospital, University of California 94110
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19
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Müller HM, Ranucci L, Pozio E, Crisanti A. A method for collecting large quantities of Cryptosporidium parasites. ACTA ACUST UNITED AC 1993; 9:261-3. [PMID: 15463774 DOI: 10.1016/0169-4758(93)90072-n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The intestinal mucoso may be regarded as a potential and abundant source of Cryptosporidium parvurn parasites from which all developmental stages might be collected. If intracellular stages could be recovered from the brush border, many of the limitations concerned with the use of oocysts and in vitro cultures may be overcome. Hans-Michael Muller, Lorella Ranucci, Edoordo Pozio and Andrea Crisonti discuss here how this can be done.
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Affiliation(s)
- H M Müller
- Istituto di Para-ssitologia, University di Roma La Sapienza, Piozzole le Aldo Moro 5, 00185 Rome, Italy
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Abstract
With the emergence of Cryptosporidium parvum as a major pathogen encountered in human and veterinary clinical practice, a need for increased knowledge of the cellular- and immuno-biology of this Apicomplexan parasite has developed. Initial work has used paradigms taken from other Apicomplexans, especially Plasmodium, Toxoplasma and Eimeria, as a starting point. In this article, Carolyn Petersen discusses the observation that in these organisms, molecular targets of antibodies (which have protective value, in vivo, against disease) have frequently been located in the apical complex or on the surface of the invasive stages of the parasite and appear to mediate biologically crucial processes including motility, attachment to the host cell, modification of the host membrane, and entry into the host cell. Molecular-biology approaches to the study of enzymes and of structural proteins which mediate motility are also considered. Invasion mechanisms, biochemical pathways and motility may involve molecules that will prove susceptible to immunotherapeutic or chemotherapeutic interruption of cryptosporidiosis.
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Affiliation(s)
- C Petersen
- Parasitology Laboratory and the Department of Medicine, San Francisco General Hospital, University of California at San Francisco, San Francisco, CA 94110, USA
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Petersen C, Gut J, Doyle PS, Crabb JH, Nelson RG, Leech JH. Characterization of a > 900,000-M(r) Cryptosporidium parvum sporozoite glycoprotein recognized by protective hyperimmune bovine colostral immunoglobulin. Infect Immun 1992; 60:5132-8. [PMID: 1452347 PMCID: PMC258288 DOI: 10.1128/iai.60.12.5132-5138.1992] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cryptosporidium parvum, a zoonotic Apicomplexan pathogen, causes profound diarrhea, malnutrition, and dehydration in patients with AIDS. A less severe, self-limited disease occurs in immunocompetent individuals, particularly children, animal handlers, and residents of the developing world. Very little is known about the biology of the organism, the pathophysiology of the disease process, or the mechanism of protective immunity. There is no effective therapy for cryptosporidiosis, but hyperimmune bovine colostrum raised against Cryptosporidium oocysts and sporozoites has ameliorated infection and disease in some patients with AIDS, and a variety of monoclonal antibodies, as well as hyperimmune bovine colostrum, have significantly reduced cryptosporidial infection of mice and calves. We report here the identification and initial characterization of a > 900,000-M(r) Cryptosporodium sporozoite glycoprotein (GP900) that is a prominent antigen recognized by protective hyperimmune bovine colostral immunoglobulin. Three of six murine anticryptosporidial monoclonal antibodies reacted with GP900, indicating that the molecule is highly immunogenic in mice as well as in cows. GP900 is Triton X-100 soluble and N glycosylated. Western blotting of the N-deglycosylated protein, detected with antibodies eluted from recombinant clones expressing a partial GP900 fusion protein, suggested that the polypeptide backbone of the glycoprotein has an M(r) of < 190,000. GP900 is encoded by a single-copy gene that resides on the largest Cryptosporidium chromosome.
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Affiliation(s)
- C Petersen
- Parasitology Laboratory, San Francisco General Hospital, California
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