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He W, Hao G, Xiong C, Xiao J, Pu J, Chen H, Xu L, Zhu Y, Yang G. Protection against Eimeria intestinalis infection in rabbits immunized with the recombinant elongation factors EF1α and EFG. Infect Immun 2023; 91:e0020823. [PMID: 37823630 PMCID: PMC10652966 DOI: 10.1128/iai.00208-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 08/25/2023] [Indexed: 10/13/2023] Open
Abstract
Eimeria intestinalis is the most pathogenic species of rabbit coccidiosis, causing weight loss, diarrhea, and even acute death. The currently used anticoccidial drugs against E. intestinalis in rabbits are associated with drug resistance and residues. Immunological control might be a potential alternative. We cloned and expressed the E. intestinalis recombinant EF1α and EFG (rEi-EF1α and rEi-EFG, respectively). Rabbits were immunized subcutaneously every 14 days with 100 µg of rEi-EF1α and rEi-EFG and followed by 5 × 104 E. intestinalis sporulated oocysts orally challenge. Serum samples were collected every 7 days to measure the levels of specific antibodies and cytokines. On post-challenge day 14, rabbits were sacrificed and the anticoccidial index was evaluated. The rabbits of PBS challenged groups exhibited anorexia, diarrhea, marked intestinal wall thickening, and white nodules that formed patches, while rabbits from the rEi-EF1α or rEi-EFG challenged group exhibited milder symptoms. The rEi-EF1α group showed a 75.18% oocyst reduction and 89.01%wt gain; the rEi-EFG group had a 60.58% oocyst reduction and 56.04%wt gain. After vaccination, specific IgG levels increased and stayed high (P < 0.05). The IL-4 and IL-2 levels of rEi-EF1α immunized groups showed a significant increase after immunization (P < 0.05). Both rEi-EF1α and rEi-EFG could induce humoral and cellular immune responses. In contrast, rabbits immunized with rEi-EF1α were better protected from challenge by E. intestinalis than rEi-EFG.
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Affiliation(s)
- Wei He
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Sichuan, China
| | - Ge Hao
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Sichuan, China
| | - Changming Xiong
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Sichuan, China
| | - Jie Xiao
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Sichuan, China
| | - Jiayan Pu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Sichuan, China
| | - Hao Chen
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Sichuan, China
| | - Liwen Xu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Sichuan, China
| | - Yuhua Zhu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Sichuan, China
| | - Guangyou Yang
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Wenjiang, Sichuan, China
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Recombinant AMA1 Virus-like Particle Antigen for Serodiagnosis of Toxoplasma gondii Infection. Biomedicines 2022; 10:biomedicines10112812. [PMID: 36359332 PMCID: PMC9687185 DOI: 10.3390/biomedicines10112812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/27/2022] [Accepted: 10/30/2022] [Indexed: 11/06/2022] Open
Abstract
Toxoplasmosis diagnosis predominantly relies on serology testing via enzyme-linked immunosorbent assay (ELISA), but these results are highly variable. Consequently, various antigens are being evaluated to improve the sensitivity and specificity of toxoplasmosis serological diagnosis. Here, we generated Toxoplasma gondii virus-like particles displaying AMA1 of T. gondii and evaluated their diagnostic potential. We found that AMA1 VLPs were highly sensitive and reacted with the sera acquired from mice infected with either T. gondii ME49 or RH strains. The overall IgG and IgM antibody responses elicited by AMA1 VLPs were substantially higher than those induced by the conventionally used T. gondii lysate antigen (TLA). Importantly, AMA1 VLPs were capable of detecting parasitic infection with T. gondii RH and ME49 as early as 1 week post-infection, even when mice were exposed to low infectious doses (5 × 103 and 10 cysts, respectively). AMA1 VLPs also did not cross-react with the immune sera acquired from Plasmodium berghei-infected mice. Compared to TLA, stronger antibody responses were induced by AMA1 VLPs when tested using T. gondii-infected human sera. The sensitivities and specificities of the two antigens were substantially different, with AMA1 VLPs demonstrating over 90% sensitivity and specificity, whereas these values were in the 70% range for the TLA. These results indicated that AMA1 VLPs can detect infections of both T. gondii ME49 and RH at an early stage of infection caused by very low infection doses in mice, and these could be used for serological diagnosis of human toxoplasmosis.
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Gathercole R, Tranfield E, Xia D, Perez-Cordon G, Robinson G, Timofte D, Zendri F, Chalmers RM. Analysis of Cryptosporidium spp. from clinical samples by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. J Appl Microbiol 2021; 131:1840-1847. [PMID: 33735496 DOI: 10.1111/jam.15077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/09/2021] [Accepted: 03/13/2021] [Indexed: 01/03/2023]
Abstract
AIM To purify Cryptosporidium spp. oocysts from clinical stool samples and evaluate using an up-to-date mass spectrometry protocol producing high-quality reference spectra. METHODS AND RESULTS A refined purification protocol was developed for oocysts from stools, involving salt flotation and potassium bromide density centrifugation. Purified oocysts were prepared for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) by formic acid extraction, and the extracts analysed using the Bruker MALDI Biotyper system. Individual spectral markers were identified by their specific mass peaks. Cryptosporidium parvum oocysts (Iowa strain) propagated in vivo, and C. parvum (n = 2) and Cryptosporidium hominis (n = 1) oocysts from clinical stool samples produced distinct spectra that were considered specific to Cryptosporidium spp. with no evidence of contamination. CONCLUSIONS The production of distinct spectra demonstrated the utility of the purification method for oocysts from clinical stool samples and provided reference spectra. SIGNIFICANCE AND IMPACT OF THE STUDY The use of MALDI-TOF MS and other mass spectrometry techniques has been limited previously to C. parvum oocysts propagated in vivo. Appropriate purification of oocysts can achieve sufficient biomass, enabling analysis by MALDI-TOF MS and potentially other mass spectrometry platforms, facilitating peptide and protein discovery and identification of biomarkers from a much wider range of Cryptosporidium spp. from natural infections.
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Affiliation(s)
- R Gathercole
- School of Biomedical, Nutritional and Sport Sciences, School of Biomedical, Nutritional and Sport Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - E Tranfield
- Bruker Microbiology & Diagnostics, Bruker, Coventry, UK
| | - D Xia
- Comparative Biomedical Sciences, Royal Veterinary College, University of London, London, UK
| | - G Perez-Cordon
- Cryptosporidium Reference Unit, Public Health Wales Microbiology and Health Protection, Singleton Hospital, Swansea, Wales, UK.,Swansea University Medical School, Singleton Park, Swansea, Wales, UK
| | - G Robinson
- Cryptosporidium Reference Unit, Public Health Wales Microbiology and Health Protection, Singleton Hospital, Swansea, Wales, UK.,Swansea University Medical School, Singleton Park, Swansea, Wales, UK
| | - D Timofte
- Institute of Infection, Veterinary and Ecological Sciences, Department of Veterinary Anatomy, Physiology and Pathology, University of Liverpool, Cheshire, UK
| | - F Zendri
- Institute of Infection, Veterinary and Ecological Sciences, Department of Veterinary Anatomy, Physiology and Pathology, University of Liverpool, Cheshire, UK
| | - R M Chalmers
- Cryptosporidium Reference Unit, Public Health Wales Microbiology and Health Protection, Singleton Hospital, Swansea, Wales, UK.,Swansea University Medical School, Singleton Park, Swansea, Wales, UK
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Matsubayashi M, Minoura C, Kimura S, Tani H, Furuya M, Lillehoj HS, Matsuda H, Takenaka S, Hatta T, Tsuji N, Sasai K. Identification of Eimeria acervulina conoid antigen using chicken monoclonal antibody. Parasitol Res 2016; 115:4123-4128. [DOI: 10.1007/s00436-016-5185-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 06/23/2016] [Indexed: 10/21/2022]
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Heimburg-Molinaro J, Priest JW, Live D, Boons GJ, Song X, Cummings RD, Mead JR. Microarray analysis of the human antibody response to synthetic Cryptosporidium glycopeptides. Int J Parasitol 2013; 43:901-7. [PMID: 23856596 PMCID: PMC3937990 DOI: 10.1016/j.ijpara.2013.05.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/20/2013] [Accepted: 05/22/2013] [Indexed: 12/13/2022]
Abstract
Glycoproteins expressed by Cryptosporidium parvum are immunogenic in infected individuals but the nature of the epitopes recognised in C. parvum glycoproteins is poorly understood. Since a known immunodominant antigen of Cryptosporidium, the 17kDa glycoprotein, has previously been shown to bind to lectins that recognise the Tn antigen (GalNAcα1-Ser/Thr-R), a large number of glycopeptides with different Tn valency and presentation were prepared. In addition, glycopeptides were synthesised based on a 40kDa cryptosporidial antigen, a polymorphic surface glycoprotein with varying numbers of serine residues, to determine the reactivity with sera from C. parvum-infected humans. These glycopeptides and non-glycosylated peptides were used to generate a glycopeptide microarray to allow screening of sera from C. parvum-infected individuals for the presence of IgM and IgG antibodies. IgG but not IgM in sera from C. parvum-infected individuals bound to multivalent Tn antigen epitopes presented on glycopeptides, suggesting that glycoproteins from C. parvum that contain the Tn antigen induce immune responses upon infection. In addition, molecular differences in glycosylated peptides (e.g. substituting Ser for Thr) as well as the site of glycosylation had a pronounced effect on reactivity. Lastly, pooled sera from individuals infected with either Toxoplasma or Plasmodium were also tested against the modified Cryptosporidium peptides and some sera showed specific binding to glycopeptide epitopes. These studies reveal that specific anti-glycopeptide antibodies that recognise the Tn antigen may be useful diagnostically and in defining the roles of parasite glycoconjugates in infections.
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Affiliation(s)
| | - Jeffrey W. Priest
- Division of Foodborne, Waterborne, and Enteric Diseases,
Centers for Disease Control and Prevention, Decatur, GA 30033, USA
| | - David Live
- Complex Carbohydrate Research Center, University of
Georgia, Athens, GA, USA
| | - Geert-Jan Boons
- Complex Carbohydrate Research Center, University of
Georgia, Athens, GA, USA
| | - Xuezheng Song
- Department of Biochemistry, Emory University, Atlanta, GA
30322, USA
| | | | - Jan R. Mead
- Department of Pediatrics, Emory University, Atlanta, GA
30322, USA
- Atlanta VA Medical Center, Decatur, GA 30033, USA
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Matsubayashi M, Teramoto-Kimata I, Uni S, Lillehoj HS, Matsuda H, Furuya M, Tani H, Sasai K. Elongation factor-1α is a novel protein associated with host cell invasion and a potential protective antigen of Cryptosporidium parvum. J Biol Chem 2013; 288:34111-34120. [PMID: 24085304 DOI: 10.1074/jbc.m113.515544] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The phylum Apicomplexa comprises obligate intracellular parasites that infect vertebrates. All invasive forms of Apicomplexa possess an apical complex, a unique assembly of organelles localized to the anterior end of the cell and involved in host cell invasion. Previously, we generated a chicken monoclonal antibody (mAb), 6D-12-G10, with specificity for an antigen located in the apical cytoskeleton of Eimeria acervulina sporozoites. This antigen was highly conserved among Apicomplexan parasites, including other Eimeria spp., Toxoplasma, Neospora, and Cryptosporidium. In the present study, we identified the apical cytoskeletal antigen of Cryptosporidium parvum (C. parvum) and further characterized this antigen in C. parvum to assess its potential as a target molecule against cryptosporidiosis. Indirect immunofluorescence demonstrated that the reactivity of 6D-12-G10 with C. parvum sporozoites was similar to those of anti-β- and anti-γ-tubulins antibodies. Immunoelectron microscopy with the 6D-12-G10 mAb detected the antigen both on the sporozoite surface and underneath the inner membrane at the apical region of zoites. The 6D-12-G10 mAb significantly inhibited in vitro host cell invasion by C. parvum. MALDI-TOF/MS and LC-MS/MS analysis of tryptic peptides revealed that the mAb 6D-12-G10 target antigen was elongation factor-1α (EF-1α). These results indicate that C. parvum EF-1α plays an essential role in mediating host cell entry by the parasite and, as such, could be a candidate vaccine antigen against cryptosporidiosis.
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Affiliation(s)
- Makoto Matsubayashi
- Department of Food and Nutrition, Osaka Yuhigaoka Gakuen Junior College, Tennoji-ku, Osaka 543-0073, Japan; Bacterial and Parasitic Disease Research Division, National Institute of Animal Health, National Agricultural and Food Research Organization, Tsukuba, Ibaraki 305-0856, Japan
| | - Isao Teramoto-Kimata
- Department of Parasitology, Graduate School of Medicine, Osaka City University, Abeno-ku, Osaka 545-8585, Japan
| | - Shigehiko Uni
- Department of Parasitology, Graduate School of Medicine, Osaka City University, Abeno-ku, Osaka 545-8585, Japan; Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Hyun S Lillehoj
- United States Department of Agriculture, Animal Biosciences and Biotechnology Laboratory, Beltsville Agricultural Research Center, Beltsville, Maryland 20705
| | - Haruo Matsuda
- Laboratory of Immunobiology, Department of Molecular and Applied Biosciences, Graduate School of Biosphere Sciences, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8528, Japan
| | - Masaru Furuya
- Department of Veterinary Internal Medicine, Division of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Izumisano, Osaka 598-8531, Japan
| | - Hiroyuki Tani
- Department of Veterinary Internal Medicine, Division of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Izumisano, Osaka 598-8531, Japan
| | - Kazumi Sasai
- Department of Veterinary Internal Medicine, Division of Veterinary Science, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Izumisano, Osaka 598-8531, Japan.
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Extracorporeal shock-wave therapy for supraspinatus calcifying tendinitis: a randomized clinical trial comparing two different energy levels. Phys Ther 2012; 92:1376-85. [PMID: 22745199 DOI: 10.2522/ptj.20110252] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Extracorporeal shock-wave therapy (ESWT) represents a valid intervention in the treatment of people with supraspinatus calcifying tendinitis (SCT), but there is limited evidence for the useful range of ESWT doses. OBJECTIVE The aim of this study was to compare 2 different ranges of energy flux density in treatment of SCT with ESWT. DESIGN This study was designed as a single-blind randomized clinical trial. SETTING This study was performed in a university hospital. PATIENTS Forty-six patients with SCT were randomly assigned to 2 groups that received different therapeutic energy doses of ESWT: (1) group A received ESWT at an energy level of 0.20 mJ/mm², and (2) group B received ESWT at an energy level of 0.10 mJ/mm². INTERVENTION The treatment protocol consisted of 4 sessions performed once a week. MEASUREMENTS The change in mean Constant Murley Scale (CMS) scores at 3 and 6 months was the primary endpoint. The change in the mean visual analog scale (VAS) scores from baseline to 3 and 6 months after the intervention and radiographic change in size of calcium deposits were evaluated as secondary endpoints. At 12 months, pain relief was assessed using a numeric rating scale. RESULTS Significant clinical improvement based on mean CMS scores was observed after 6 months in group A (X=79.43, SD=10.33) compared with group B (X=57.91, SD=6.53). Likewise, after 6 months, a significant decrease in VAS scores was found in group A (X=2.09, SD=1.54) compared with group B (X=5.36, SD=0.78). Calcific deposits disappeared in the same percentage of patients in both groups. LIMITATIONS The small sample size and lack of a control group were limitations of the study. CONCLUSIONS In ESWT for SCT, an energy level of 0.20 mJ/mm² appears to be more effective than an energy level of 0.10 mJ/mm² in pain relief and functional improvement.
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In vitro assessment of anticryptosporidial efficacy and cytotoxicity of adenosine analogues using a SYBR Green real-time PCR method. J Antimicrob Chemother 2011; 66:560-3. [DOI: 10.1093/jac/dkq522] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Morphological changes and viability ofCryptosporidium parvumsporozoites after excystation in cell-free culture media. Parasitology 2010; 137:1861-6. [DOI: 10.1017/s0031182010000685] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYCryptosporidium parvum,belonging to the phylum Apicomplexa, is a major cause of waterborne gastroenteritis throughout the world. The sporozoites are thought to invade host enterocytes using an active process termed gliding motility. However, the biological and morphological changes within the sporozoites during this process are not fully understood. In the present study, excysted sporozoites ofC. parvumwere analysed ultrastructurallyin vitroand their viability was evaluated using fluorescent dyes. The sporozoites excysted from oocysts changed morphologically from banana-shaped to rod-shaped and finally to a rounded shape, in culture media in 3 h. Transmission microscopy revealed that the distance between the apical end and the nucleus was markedly reduced, dense granules were present close to the rhoptry in the apical region, amylopectin granules were absent, and membranes of round sporozoites were less clear. A fluorescent assay showed that the rate of survival decreased from 89% to 56% at 0–3 h (84·3% for banana-shaped and 49·2% for rod-shaped sporozoites). Therefore, post-excysted sporozoitesin vitrounderwent morphological changes and a rapid loss of viability. This staining method is useful, inexpensive and provides an alternative to more costly and intensive flow cytometric assays or infectivity assays with host cellsin vitro.
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Electron microscopic observation of cytoskeletal frame structures and detection of tubulin on the apical region of Cryptosporidium parvum sporozoites. Parasitology 2007; 135:295-301. [DOI: 10.1017/s003118200700385x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYCryptosporidium parvum is an intracellular protozoan parasite belonging to the phylum Apicomplexa, and a major cause of waterborne gastroenteritis throughout the world. Invasive zoites of apicomplexan parasites, including C. parvum, are thought to have characteristic organelles on the apical apex; however, compared with other parasites, the cytoskeletal ultrastructure of C. parvum zoites is poorly understood. Thus, in the present study, we ultrastructurally examined C. parvum sporozoites using electron microscopy to clarify the framework of invasive stages. Consequently, at the apical end of sporozoites, 3 apical rings and an electron-dense collar were seen. Two thick central microtubules were seen further inside sporozoites and extended to the posterior region. Using anti-α and -β tubulin antibodies generated from sea urchin and rat brain, both antibodies cross-reacted at the apical region of sporozoites in immunofluorescent morphology. The molecular mass of C. parvum α tubulin antigen was 50 kDa by Western blotting and the observed apical cytoskeletal structures were shown to be composed of α tubulin by immunoelectron microscopy. These results suggested that C. parvum sporozoites were clearly different in their cytoskeletal structure from those of other apicomplexan parasites.
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Shirley MW, Smith AL, Blake DP. Challenges in the successful control of the avian coccidia. Vaccine 2006; 25:5540-7. [PMID: 17224208 DOI: 10.1016/j.vaccine.2006.12.030] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 12/08/2006] [Accepted: 12/11/2006] [Indexed: 11/28/2022]
Abstract
Eimeria species infect livestock in a host-specific manner and are the cause of the disease, coccidiosis. Control of Eimeria species is essential and is currently dominated by chemotherapy; with vaccination using formulations of live wild-type or attenuated parasites an increasing option. A new generation of subunit, live-vector or DNA vaccination strategies is being sought and determining the identity of suitable antigens remains difficult. Some past and present methods of controlling avian coccidia are discussed briefly and we describe progress with a novel approach to identify immunoprotective antigens as vaccine candidates.
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Affiliation(s)
- Martin W Shirley
- Molecular Parasitology, Institute for Animal Health, Compton, Nr. Newbury, Berkshire RG20 7NN, United Kingdom.
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Abstract
The Eimeria species, causative agents of the disease coccidiosis, are genetically complex protozoan parasites endemic in livestock. Drug resistance remains commonplace among the Eimeria, and alternatives to chemotherapeutic control are being sought. Vaccines based upon live formulations of parasites are effective, but production costs are high, stimulating demand for a recombinant subunit vaccine. The identity of antigens suitable for inclusion in such vaccines remains elusive. Selection of immunoprotective antigens of the Eimeria species as vaccine candidates based upon recognition by the host immune system has been unsuccessful, obscured by the considerable number of molecules that are immunogenic but not immunoprotective. This is a common problem which characterizes work with most eukaryotic parasites. The identification of a selective criterion to directly access genetic loci that encode immunoprotective antigens of Eimeria maxima using a mapping strategy based upon parasite genetics, immune selection and DNA fingerprinting promises to revolutionize the process of antigen discovery. Linkage analyses of DNA markers amplified from populations of recombinant parasites defined by an ability to escape parent-specific deleterious selection by strain-specific immunity and chemotherapy has revealed four discrete regions within the E. maxima genome linked to escape from a protective immune response. These regions now form the basis of detailed study to identify antigens as candidates for inclusion in future vaccination strategies.
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Affiliation(s)
- D P Blake
- Enteric Immunology Group, Institute for Animal Health, Compton, Nr. Newbury, Berkshire, UK.
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