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Morrison WI, Aguado A, Sheldrake TA, Palmateer NC, Ifeonu OO, Tretina K, Parsons K, Fenoy E, Connelley T, Nielsen M, Silva JC. CD4 T Cell Responses to Theileria parva in Immune Cattle Recognize a Diverse Set of Parasite Antigens Presented on the Surface of Infected Lymphoblasts. THE JOURNAL OF IMMUNOLOGY 2021; 207:1965-1977. [PMID: 34507950 DOI: 10.4049/jimmunol.2100331] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/22/2021] [Indexed: 12/23/2022]
Abstract
Parasite-specific CD8 T cell responses play a key role in mediating immunity against Theileria parva in cattle (Bos taurus), and there is evidence that efficient induction of these responses requires CD4 T cell responses. However, information on the antigenic specificity of the CD4 T cell response is lacking. The current study used a high-throughput system for Ag identification using CD4 T cells from immune animals to screen a library of ∼40,000 synthetic peptides representing 499 T. parva gene products. Use of CD4 T cells from 12 immune cattle, representing 12 MHC class II types, identified 26 Ags. Unlike CD8 T cell responses, which are focused on a few dominant Ags, multiple Ags were recognized by CD4 T cell responses of individual animals. The Ags had diverse properties, but included proteins encoded by two multimember gene families: five haloacid dehalogenases and five subtelomere-encoded variable secreted proteins. Most Ags had predicted signal peptides and/or were encoded by abundantly transcribed genes, but neither parameter on their own was reliable for predicting antigenicity. Mapping of the epitopes confirmed presentation by DR or DQ class II alleles and comparison of available T. parva genome sequences demonstrated that they included both conserved and polymorphic epitopes. Immunization of animals with vaccine vectors expressing two of the Ags demonstrated induction of CD4 T cell responses capable of recognizing parasitized cells. The results of this study provide detailed insight into the CD4 T cell responses induced by T. parva and identify Ags suitable for use in vaccine development.
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Affiliation(s)
- W Ivan Morrison
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom;
| | - Adriana Aguado
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
| | - Tara A Sheldrake
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
| | - Nicholas C Palmateer
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD
| | - Olukemi O Ifeonu
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD
| | - Kyle Tretina
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD
| | - Keith Parsons
- Institute for Animal Health, Berkshire, United Kingdom
| | - Emilio Fenoy
- Biotechnological Research Institute, National University of San Martin, Buenos Aires, Argentina
| | - Timothy Connelley
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, United Kingdom
| | - Morten Nielsen
- Biotechnological Research Institute, National University of San Martin, Buenos Aires, Argentina.,Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark; and
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD.,Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD
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Nyagwange J, Tijhaar E, Ternette N, Mobegi F, Tretina K, Silva JC, Pelle R, Nene V. Characterization of the Theileria parva sporozoite proteome. Int J Parasitol 2017; 48:265-273. [PMID: 29258832 PMCID: PMC5854367 DOI: 10.1016/j.ijpara.2017.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/16/2017] [Accepted: 09/21/2017] [Indexed: 12/29/2022]
Abstract
2007 Theileria parva proteins expressed in the sporozoite were identified. Proteins include known T. parva antigens targeted by antibodies and cytotoxic T cells. Proteins predicted to be orthologs of Plasmodium falciparum sporozoite surface molecules were identified. Proteins predicted to be orthologs of P. falciparum invasion organelle proteins were identified. Proteins that may contribute to the phenomenon of bovine lymphocyte transformation were identified.
East Coast fever is a lymphoproliferative disease caused by the tick-borne protozoan parasite Theileria parva. The sporozoite stage of this parasite, harboured and released from the salivary glands of the tick Rhipicephalus appendiculatus during feeding, invades and establishes infection in bovine lymphocytes. Blocking this initial stage of invasion presents a promising vaccine strategy for control of East Coast fever and can in part be achieved by targeting the major sporozoite surface protein p67. To support research on the biology of T. parva and the identification of additional candidate vaccine antigens, we report on the sporozoite proteome as defined by LC–MS/MS analysis. In total, 4780 proteins were identified in an enriched preparation of sporozoites. Of these, 2007 were identified as T. parva proteins, representing close to 50% of the total predicted parasite proteome. The remaining 2773 proteins were derived from the tick vector. The identified sporozoite proteins include a set of known T. parva antigens targeted by antibodies and cytotoxic T cells from cattle that are immune to East Coast fever. We also identified proteins predicted to be orthologs of Plasmodium falciparum sporozoite surface molecules and invasion organelle proteins, and proteins that may contribute to the phenomenon of bovine lymphocyte transformation. Overall, these data establish a protein expression profile of T. parva sporozoites as an important starting point for further study of a parasitic species which has considerable agricultural impact.
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Affiliation(s)
- James Nyagwange
- International Livestock Research Institute, P.O. Box 30709, Nairobi, Kenya; Cell Biology and Immunology Group, Wageningen University, The Netherlands
| | - Edwin Tijhaar
- Cell Biology and Immunology Group, Wageningen University, The Netherlands
| | - Nicola Ternette
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, UK
| | - Fredrick Mobegi
- Department of Infection and Immunity, South Australian Health and Medical Research Institute, North Terrace, Adelaide 5000, South Australia, Australia
| | - Kyle Tretina
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Roger Pelle
- International Livestock Research Institute, P.O. Box 30709, Nairobi, Kenya
| | - Vishvanath Nene
- International Livestock Research Institute, P.O. Box 30709, Nairobi, Kenya.
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Nene V, Morrison WI. Approaches to vaccination against Theileria parva and Theileria annulata. Parasite Immunol 2016; 38:724-734. [PMID: 27647496 PMCID: PMC5299472 DOI: 10.1111/pim.12388] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/15/2016] [Indexed: 12/04/2022]
Abstract
Despite having different cell tropism, the pathogenesis and immunobiology of the diseases caused by Theileria parva and Theileria annulata are remarkably similar. Live vaccines have been available for both parasites for over 40 years, but although they provide strong protection, practical disadvantages have limited their widespread application. Efforts to develop alternative vaccines using defined parasite antigens have focused on the sporozoite and intracellular schizont stages of the parasites. Experimental vaccination studies using viral vectors expressing T. parva schizont antigens and T. parva and T. annulata sporozoite antigens incorporated in adjuvant have, in each case, demonstrated protection against parasite challenge in a proportion of vaccinated animals. Current work is investigating alternative antigen delivery systems in an attempt to improve the levels of protection. The genome architecture and protein-coding capacity of T. parva and T. annulata are remarkably similar. The major sporozoite surface antigen in both species and most of the schizont antigens are encoded by orthologous genes. The former have been shown to induce species cross-reactive neutralizing antibodies, and comparison of the schizont antigen orthologues has demonstrated that some of them display high levels of sequence conservation. Hence, advances in development of subunit vaccines against one parasite species are likely to be readily applicable to the other.
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Affiliation(s)
- V Nene
- The International Livestock Research Institute, Nairobi, Kenya
| | - W I Morrison
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK
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The biology of Theileria parva and control of East Coast fever – Current status and future trends. Ticks Tick Borne Dis 2016; 7:549-64. [DOI: 10.1016/j.ttbdis.2016.02.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 02/01/2016] [Accepted: 02/02/2016] [Indexed: 01/02/2023]
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Morrison WI, Connelley T, Hemmink JD, MacHugh ND. Understanding the Basis of Parasite Strain-Restricted Immunity toTheileria parva. Annu Rev Anim Biosci 2015; 3:397-418. [DOI: 10.1146/annurev-animal-022513-114152] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- W. Ivan Morrison
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, United Kingdom;
| | - Timothy Connelley
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, United Kingdom;
| | | | - Niall D. MacHugh
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, United Kingdom;
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Innes EA, Bartley PM, Rocchi M, Benavidas-Silvan J, Burrells A, Hotchkiss E, Chianini F, Canton G, Katzer F. Developing vaccines to control protozoan parasites in ruminants: Dead or alive? Vet Parasitol 2011; 180:155-63. [DOI: 10.1016/j.vetpar.2011.05.036] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Abstract
SUMMARYInfections withTheileria parvain the African buffalo are invariably asymptomatic, whereas infections in cattle usually result in clinical disease, the severity of which varies in different populations of cattle. The parasite exhibits antigenic heterogeneity, which in cattle manifests as differences between parasite strains in their cross-protective properties. A series of studies on T cell responses toT. parvain cattle have demonstrated that class I MHC-restricted cytotoxic T lymphocytes (CTL), specific for parasitized lymphoblasts, are important mediators of immunity. Cytotoxic T cell responses frequently display parasite strain-restricted specificities which appear to correlate with the capacity of strains to cross-protect. The strain specificity of CTL responses varies in animals immunized with the same parasite strain and is influenced by both host and parasite genotype. Recent studies have provided evidence that there is competition between epitopes for induction of CTL responses, which can result in a bias to strain-specific epitopes. These properties of the CTL response have important implications for vaccination. Thus, in designing a vaccine, it may be possible, by selecting parasite proteins containing appropriate CTL epitopes, to generate CTL responses that protect against a wide range of parasite strains. Although there are no comparable data on CTL responses in the buffalo, it is considered that the features of the immune response described for cattle would be advantageous for survival of parasite populations in the buffalo. Specifically, a bias in the immune responses to strain-specific determinants should favour establishment of infection in buffalo already carrying the parasite and allow fluctuation in the levels of different parasite strains during the course of persistent infection.
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Morrison WI. The biological and practical significance of antigenic variability in protective T cell responses against Theileria parva. Vet Parasitol 2007; 148:21-30. [PMID: 17580101 DOI: 10.1016/j.vetpar.2007.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The evolution of antigenically distinct pathogen strains that fail to cross-protect is well documented for pathogens controlled primarily by humoral immune responses. Unlike antibodies, which recognise native proteins, protective T cells can potentially recognise epitopes in a variety of proteins that are not necessarily displayed on the pathogen surface. Moreover, individual hosts of different MHC genotypes generally respond to different sets of epitopes. It is therefore less easy to envisage how strain restricted immunity can arise for pathogens controlled by T cell responses, particularly in antigenically complex parasites. Nevertheless, strain restricted immunity is clearly a feature of a number of parasitic infections, where immunity is known to be mediated by T cell responses. One such parasite is Theileria parva which induces potent CD8 T cell responses that play an important role in immunity. CD8 T cells specific for parasitized lymphoblasts exhibit strain specificity, which appears to correlate with the ability of parasite strains to cross-protect. Studies using recently identified T. parva antigens recognised by CD8 T cells have shown that the strain restricted nature of immunity is a consequence of the CD8 T cell response in individual animals being focused on a limited number of dominant polymorphic antigenic determinants. Responses in animals of different MHC genotypes are often directed to different parasite antigens, indicating that, at the host population level, a larger number of parasite proteins can serve as targets for the protective T cell response. Nevertheless, the finding that parasite strains show overlapping antigenic profiles, probably as a consequence of sexual recombination, suggests that induction of responses to an extended but limited set of antigens in individual animals may overcome the strain restricted nature of immunity.
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Affiliation(s)
- W I Morrison
- Division of Veterinary Clinical Sciences, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Roslin, Midlothian EH25 9RG, UK.
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Morrison WI, McKeever DJ. Current status of vaccine development against Theileria parasites. Parasitology 2007; 133 Suppl:S169-87. [PMID: 17274845 DOI: 10.1017/s0031182006001867] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The tick-borne protozoan parasites Theileria parva and Theileria annulata cause economically important diseases of cattle in tropical and sub-tropical regions. Because of shortcomings in disease control measures based on therapy and tick control, there is a demand for effective vaccines against these diseases. Vaccines using live parasites have been available for over two decades, but despite their undoubted efficacy they have not been used on a large scale. Lack of infrastructure for vaccine production and distribution, as well as concerns about the introduction of vaccine parasite strains into local tick populations have curtailed the use of these vaccines. More recently, research has focused on the development of subunit vaccines. Studies of immune responses to different stages of the parasites have yielded immunological probes that have been used to identify candidate vaccine antigens. Immunisation of cattle with antigens expressed in the sporozoite, schizont or merozoite stages has resulted in varying degrees of protection against challenge. Although the levels of protection achieved have not been sufficient to allow exploitation for vaccination, there are clearly further lines of investigation, relating to both the choice of antigens and the antigen delivery systems employed, that need to be pursued to fully explore the potential of the candidate vaccines. Improved knowledge of the molecular biology and immunology of the parasites gained during the course of these studies has also opened up opportunities to refine and improve the quality of live vaccines.
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Affiliation(s)
- W I Morrison
- Division of Veterinary Clinical Sciences, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK.
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Mertens B, Bishop R, Taracha E, Morzaria S, Nene V, Savadye D. Cloning, sequence and mRNA expression of bovine interleukin-16. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 2000; 10:425-8. [PMID: 10826703 DOI: 10.3109/10425170009015614] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A lambda gt11 cDNA library was constructed using mRNA isolated from Theileria parva-infected bovine lymphocytes. Sequencing of random clones of this library resulted in the identification of a cDNA encoding bovine interleukin-16 (IL-16). The cDNA has an open reading frame of 1134 bp, and a 3' untranslated region of 275 nucleotides with a polyadenylation signal 16 bases upstream from the poly (A) tail. The protein predicted by the cDNA sequence contains 378 amino acids and the level of amino acid homology with the corresponding part of human precursor IL-16 is 79 %. No information is available about the tissue distribution of IL-16 in cattle, therefore we investigated the expression of IL-16 mRNA in bovine lymphoid tissues by reverse-transcription polymerase chain reaction assays. To investigate the potential of IL-16 as an immunoregulatory molecule we also analysed IL-16 mRNA expression in CD4+ and CD8+T-cell clones derived from T. parva-immunised cattle.
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Affiliation(s)
- B Mertens
- International Livestock Research Institute (ILRI), Nairobi, Kenya.
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Daubenberger CA, Taracha EL, Gaidulis L, Davis WC, McKeever DJ. Bovine gammadelta T-cell responses to the intracellular protozoan parasite Theileria parva. Infect Immun 1999; 67:2241-9. [PMID: 10225880 PMCID: PMC115963 DOI: 10.1128/iai.67.5.2241-2249.1999] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
T cells bearing the gammadelta antigen receptor (gammadelta T cells) can constitute up to 50% of T cells in the peripheral blood and lymphoid organs of young cattle. We present data showing that gammadelta T cells are involved in immune responses against Theileria parva. gammadelta T cells isolated from peripheral blood mononuclear cells (PBMC) of T. parva-naive and -immune cattle proliferated in the presence of fixed or unfixed autologous T. parva-infected lymphoblasts (TpL) and heat-stressed concanavalin A (ConA)-induced blasts (ConA blasts) but not untreated ConA blasts. The specificity of response was further evaluated with a panel of gammadelta T-cell lines and clones. T-cell reactivity was blocked by GB21A, a monoclonal antibody (MAb) specific for the gammadelta T-cell receptor, but not by MAbs specific for class I and class II major histocompatibility complex (MHC) molecules. In addition, TpL but not ConA blasts from a variety of MHC-mismatched animals induced proliferation of the gammadelta T-cell lines and clones. These gammadelta T cells were found to respond to TpL infected with several different parasite stocks and failed to recognize TpL after elimination of the parasite by the theilericidal drug BW 720C. Assays for cytotoxic activity of gammadelta T cells sorted from bulk cultures of immune PBMC restimulated several times with autologous TpL demonstrated that effector cells whose specificity is similar to that of proliferating cells are generated. These results suggest that bovine gammadelta T cells are activated by and lyse T. parva-infected cells by recognizing conserved parasite-induced or parasite-derived antigens in an MHC-unrestricted fashion.
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Affiliation(s)
- C A Daubenberger
- International Livestock Research Institute (ILRI), Nairobi, Kenya.
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Brown WC, Zhao S, Logan KS, Grab DJ, Rice-Ficht AC. Identification of candidate vaccine antigens of bovine hemoparasites Theileria parva and Babesia bovis by use of helper T cell clones. Vet Parasitol 1995; 57:189-203. [PMID: 7597783 DOI: 10.1016/0304-4017(94)03120-l] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Current vaccines for bovine hemoparasites utilize live attenuated organisms or virulent organisms administered concurrently with antiparasitic drugs. Although such vaccines can be effective, for most hemoparasites the mechanisms of acquired resistance to challenge infection with heterologous parasite isolates have not been clearly defined. Selection of potentially protective antigens has traditionally made use of antibodies to identify immunodominant proteins. However, numerous studies have indicated that induction of high antibody titers neither predicts the ability of an antigen to confer protective immunity nor correlates with protection. Because successful parasites have evolved antibody evasion tactics, alternative strategies to identify protective immunogens should be used. Through the elaboration of cytokines, T helper 1-(Th1)-like T cells and macrophages mediate protective immunity against many intracellular parasites, and therefore most likely play an important role in protective immunity against bovine hemoparasites. CD4+ T cell clones specific for soluble or membrane antigens of either Theileria parva schizonts or Babesia bovis merozoites were therefore employed to identify parasite antigens that elicit strong Th cell responses in vitro. Soluble cytosolic parasite antigen was fractionated by gel filtration, anion exchange chromatography or hydroxylapatite chromatography, or a combination thereof, and fractions were tested for the ability to induce proliferation of Th cell clones. This procedure enabled the identification of stimulatory fractions containing T. parva proteins of approximately 10 and 24 kDa. Antisera raised against the purified 24 kDa band reacted with a native schizont protein of approximately 30 kDa. Babesia bovis-specific Th cell clones tested against fractionated soluble Babesia bovis merozoite antigen revealed the presence of at least five distinct antigenic epitopes. Proteins separated by gel filtration revealed four patterns of reactivity, and proteins separated by anion exchange revealed two patterns of reactivity when selected T cell clones were assayed for stimulation by antigenic fractions. Studies using a continuous-flow electrophoresis apparatus have indicated the feasibility of identifying T cell-stimulatory proteins from parasite membranes as well as from the cytosolic fraction of B. bovis merozoites. The Th cell clones reactive with these different hemoparasites expressed either unrestricted or Th1 cytokine profiles, and were generally characterized by the production of high levels of IFN-gamma. A comprehensive study of T cell and macrophage responses to defined parasite antigens will help elucidate the reasons for vaccine failure or success, and provide clues to the mechanisms of acquired immunity that are needed for vaccine development.
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Affiliation(s)
- W C Brown
- International Laboratory for Research on Animal Diseases, Nairobi, Kenya
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Morrison WI, Taracha EL, McKeever DJ. Theileriosis: progress towards vaccine development through understanding immune responses to the parasite. Vet Parasitol 1995; 57:177-87. [PMID: 7597782 DOI: 10.1016/0304-4017(94)03119-h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Studies of the immune responses of cattle to Theileria parva have provided evidence that immunity to the parasite can operate at two levels, namely the sporozoite and the schizont-infected lymphoblast. Antibodies that neutralize the infectivity of sporozoites have been detected in the serum of hyperimmunized cattle, and a recombinant sporozoite surface antigen has been shown to induce neutralizing antibodies and protection against experimental challenge. However, the immunity that develops following primary infection with T. parva is accompanied by only low levels of antibodies to sporozoites; there is overwhelming evidence that under these circumstances protection is mediated by T cell responses against infected lymphoblasts. Potent class I MHC-restricted cytotoxic T lymphocyte (CTL) responses are detected in animals recovering from infection and treatment or challenge infections. Two recent findings have provided direct evidence for the importance of these responses in immunity. First, the strain specificity of CTL in cattle immunized with one stock of the parasite was found to correlate with the subsequent susceptibility of individual animals to challenge with a heterologous cloned parasite population (in these circumstances some animals are protected whereas others are susceptible to the heterologous challenge). Second, the adoptive transfer of lymphocytes highly enriched for CD8+ T cells, from immune to naive identical twin calves, was found to protect against experimental challenge. The CTL response in individual animals appears to be directed towards a limited number of antigenic epitopes. The antigenic specificity is determined in part by class I MHC phenotype although there is evidence that other phenomena such as antigenic competition are also involved. Current efforts are directed towards identification of the parasite antigens recognized by CTL with the eventual aim of exploring their potential for vaccination.
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Affiliation(s)
- W I Morrison
- AFRC Institute for Animal Health, Compton, Near Newbury, UK
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Morrison W, Taracha E, McKeever D. Contribution of T-cell responses to immunity and pathogenesis in infections with Theileria parva. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/0169-4758(95)80099-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Grab DJ, Baldwin CL, Brown WC, Innes EA, Lonsdale-Eccles JD, Verjee Y. Immune CD4+ T cells specific for Theileria parva-infected lymphocytes recognize a 24-kilodalton protein. Infect Immun 1992; 60:3892-6. [PMID: 1354201 PMCID: PMC257404 DOI: 10.1128/iai.60.9.3892-3896.1992] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Theileria parva is a protozoan parasite that infects and transforms bovine lymphocytes. Here we report the partial purification of a T. parva-specific protein from infected lymphocytes that is recognized by CD4+ parasite-specific T-cell clones derived from immune cattle. T. parva-infected lymphocytes were homogenized in Dulbecco's phosphate-buffered saline in the presence of protease inhibitors. The antigen was purified from a postmicrosomal supernatant by using a combination of DEAE-cellulose chromatography and hydroxylapatite column chromatography. After labelling with 125I, the antigen preparation was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and found to contain 8 to 10 proteins. This preparation was subjected to chromatography in phosphate-buffered saline on HPLC TSK-250/125 columns coupled in tandem. A radiolabelled protein of M(r) 24,000 correlated with antigenic activity.
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Affiliation(s)
- D J Grab
- International Laboratory for Research on Animal Diseases, Nairobi, Kenya
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Baldwin CL, Iams KP, Brown WC, Grab DJ. Theileria parva: CD4+ helper and cytotoxic T-cell clones react with a schizont-derived antigen associated with the surface of Theileria parva-infected lymphocytes. Exp Parasitol 1992; 75:19-30. [PMID: 1353459 DOI: 10.1016/0014-4894(92)90118-t] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Theileria parva is a protozoan parasite which infects and transforms bovine lymphocytes, resulting in a fatal lymphoproliferative disease. There is evidence that immunity to the intralymphocytic schizont stage is mediated by T cells. We have previously reported derivation of CD4+ T-cell clones which recognize parasite-derived antigens presented on the surface of infected cells in conjunction with MHC molecules and partial characterization of the antigens. The present study further evaluated one of these antigens, demonstrating that it could be derived from cells infected with different parasite stocks as well as from purified theilerial schizonts and that it was recognized by primed, but not unprimed, bovine lymphocytes including cytolytic CD4+ T cells. Using a cloned CD4+ cytolytic cell line, lysis of schizont-infected cells was shown to be MHC-restricted but not parasite-strain restricted. In addition we demonstrated that T cells which respond to the HSS antigen preparation were generated in cattle immunized with parasites from any of the three subspecies of T. parva. The antigenic material was fractionated by sequential subjection to anion-exchange chromatography, hydroxylapatite chromatography, and gel filtration using HPLC, which resulted in recovery of approximately 20% of the antigenic material with more than 10(6)-fold purification in selected fractions. To assess the molecular size of the proteins in the highly purified antigenic fractions, the T. parva-infected lymphocytes were metabolically labeled before fractionation with 3H-amino acids and the material was analyzed by SDS-polyacrylamide gel electrophoresis and liquid scintillation counting of gel slices. The major protein in these fractions had a molecular mass of 9-10 kDa.
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Affiliation(s)
- C L Baldwin
- International Laboratory for Research on Animal Diseases, Nairobi, Kenya
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Brown WC, Logan KS. Babesia bovis: Bovine helper T cell lines reactive with soluble and membrane antigens of merozoites. Exp Parasitol 1992; 74:188-99. [PMID: 1371257 DOI: 10.1016/0014-4894(92)90046-d] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Babesia bovis-specific T cell lines were established from cattle infected with either tick-derived or cultured parasites by stimulation of peripheral blood mononuclear cells with a crude parasite membrane fraction. Induction and enrichment of CD4+ T cells occurred over time. All cell lines responded vigorously and in a dose-dependent, MHC-restricted manner to intact merozoites, and to soluble and membrane fractions derived from merozoites by homogenization and high-speed centrifugation. Solubilization of the membrane fraction with nondenaturing zwitterionic or nonionic detergents yielded antigenic extracts which also stimulated the T cells. However, a differential response was observed, in that cell lines from one animal proliferated vigorously to the detergent extracts of the membrane fraction, whereas cell lines from a second animal proliferated only weakly to these extracts. SDS-PAGE analysis revealed common protein bands of 90 and 22 kDa in the various immunogenic fractions. Cell lines from the animal infected with cultured parasites also responded to parasite culture supernatant "exoantigens" and to the related parasite, Babesia bigemina. We conclude that antigens present in merozoite membranes and soluble parasite extracts preferentially stimulate CD4+ T cells from cattle immune to Babesia bovis. The differential pattern of response of T cell lines from different cattle suggests that more than one protein or epitope is immunodominant for T cells.
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Affiliation(s)
- W C Brown
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station 77843-4467
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Dobbelaere DA, Roditi IJ, Coquerelle TM, Kelke C, Eichhorn M, Williams RO. Lymphocytes infected with Theileria parva require both cell-cell contact and growth factor to proliferate. Eur J Immunol 1991; 21:89-95. [PMID: 1899385 DOI: 10.1002/eji.1830210114] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Lymphocytes infected with the intracellular parasite Theileria parva proliferate continuously as lymphoblastoid cell lines. We have previously shown that the continuous proliferation of the T. parva-infected (Tpi) cell line TpM(803) is mediated in part by an autocrine mechanism (Dobbelaere, D. A. E. et al., Proc. Natl. Acad. Sci. USA 1988. 85:4730). We now report that continuous proliferation also requires surface stimulation through cell-cell contact. Under standard culture conditions this surface stimulus is provided by the infected cells themselves, but it can also be provided by uninfected lymphocytes or macrophages. The ability to respond to surface stimulation is critically dependent on the presence of the parasite in the host cell and is lost within 48 h after the elimination of the parasite from the host cell cytoplasm by treatment with the theilericidal drug BW720c. Tpi cells also secrete a growth factor which is able to support the proliferation of diluted Tpi cells. Growth factor secretion is rapidly lost upon elimination of the parasite. Moreover, inhibition experiments using anti-interleukin 2 (IL 2) antibodies show that IL 2 is involved in the proliferation of the Tpi cell lines TpM(803) and IN10. T cell proliferation is dependent on a number of costimulatory signals which are normally provided by accessory cells. The finding that Tpi cells can mutually stimulate each other to grow in the absence of conventional accessory cells helps to explain how they can escape the normal constraints on T cell growth, allowing them to invade and multiply in non-lymphoid as well as lymphoid tissues.
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Affiliation(s)
- D A Dobbelaere
- Kernforschungszentrum Karlsruhe, Institut für Genetik und Toxikologie, Karlsruhe
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Morrison WI, Goddeeris BM. Cytotoxic T cells in immunity to Theileria parva in cattle. Curr Top Microbiol Immunol 1990; 155:79-93. [PMID: 2137767 DOI: 10.1007/978-3-642-74983-4_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- W I Morrison
- International Laboratory for Research on Animal Diseases, Nairobi, Kenya
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Brown WC, Sugimoto C, Conrad PA, Grab DJ. Differential response of bovine T-cell lines to membrane and soluble antigens of Theileria parva schizont-infected cells. Parasite Immunol 1989; 11:567-83. [PMID: 2533341 DOI: 10.1111/j.1365-3024.1989.tb00921.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
T-cell lines generated from Theileria parva-immune cattle were used to identify antigens associated with schizont-infected lymphoblastoid cells. Homogenates prepared from T. parva-infected cells were fractionated by differential centrifugation, and antigenically distinct soluble and membrane-bound antigens were detected by the differential stimulation of cell lines derived from two animals. Activity in the soluble fraction was not attributable to either a mitogen or interleukin 2. Activity in the membrane fraction was associated with schizont membranes as indicated by the presence in this fraction of a parasite protein detected by immunoblot analysis using a schizont-specific monoclonal antibody. Elimination of intracellular schizonts over time, using the anti-theilerial drug, parvaquone, resulted in a concomitant loss of antigenicity in infected cells and in subcellular fractions prepared from drug-treated cells, demonstrating that stimulation of Theileria-specific helper and cytotoxic T-cell responses is associated with the presence of the parasite.
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Affiliation(s)
- W C Brown
- International Laboratory for Research on Animal Diseases (ILRAD), Nairobi, Kenya
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