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Ramsay JD, Ueti MW, Johnson WC, Scoles GA, Knowles DP, Mealey RH. Lymphocytes and macrophages are infected by Theileria equi, but T cells and B cells are not required to establish infection in vivo. PLoS One 2013; 8:e76996. [PMID: 24116194 PMCID: PMC3792048 DOI: 10.1371/journal.pone.0076996] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 09/04/2013] [Indexed: 11/18/2022] Open
Abstract
Theileria equi has a biphasic life cycle in horses, with a period of intraleukocyte development followed by patent erythrocytic parasitemia that causes acute and sometimes fatal hemolytic disease. Unlike Theileria spp. that infect cattle (Theileria parva and Theileria annulata), the intraleukocyte stage (schizont) of Theileria equi does not cause uncontrolled host cell proliferation or other significant pathology. Nevertheless, schizont-infected leukocytes are of interest because of their potential to alter host cell function and because immune responses directed against this stage could halt infection and prevent disease. Based on cellular morphology, Theileria equi has been reported to infect lymphocytes in vivo and in vitro, but the specific phenotype of schizont-infected cells has yet to be defined. To resolve this knowledge gap in Theileria equi pathogenesis, peripheral blood mononuclear cells were infected in vitro and the phenotype of infected cells determined using flow cytometry and immunofluorescence microscopy. These experiments demonstrated that the host cell range of Theileria equi was broader than initially reported and included B lymphocytes, T lymphocytes and monocyte/macrophages. To determine if B and T lymphocytes were required to establish infection in vivo, horses affected with severe combined immunodeficiency (SCID), which lack functional B and T lymphocytes, were inoculated with Theileria equi sporozoites. SCID horses developed patent erythrocytic parasitemia, indicating that B and T lymphocytes are not necessary to complete the Theileria equi life cycle in vivo. These findings suggest that the factors mediating Theileria equi leukocyte invasion and intracytoplasmic differentiation are common to several leukocyte subsets and are less restricted than for Theileria annulata and Theileria parva. These data will greatly facilitate future investigation into the relationships between Theileria equi leukocyte tropism and pathogenesis, breed susceptibility, and strain virulence.
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Affiliation(s)
- Joshua D. Ramsay
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, Washington, United States of America
- * E-mail:
| | - Massaro W. Ueti
- Animal Disease Research Unit, Agricultural Research Service, USDA, Pullman, Washington, United States of America
| | - Wendell C. Johnson
- Animal Disease Research Unit, Agricultural Research Service, USDA, Pullman, Washington, United States of America
| | - Glen A. Scoles
- Animal Disease Research Unit, Agricultural Research Service, USDA, Pullman, Washington, United States of America
| | - Donald P. Knowles
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, Washington, United States of America
- Animal Disease Research Unit, Agricultural Research Service, USDA, Pullman, Washington, United States of America
| | - Robert H. Mealey
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, Washington, United States of America
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A Theileria parva isolate of low virulence infects a subpopulation of lymphocytes. Infect Immun 2011; 80:1267-73. [PMID: 22202119 DOI: 10.1128/iai.05085-11] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Theileria parva is a tick-transmitted protozoan parasite that infects and transforms bovine lymphocytes. We have previously shown that Theileria parva Chitongo is an isolate with a lower virulence than that of T. parva Muguga. Lower virulence appeared to be correlated with a delayed onset of the logarithmic growth phase of T. parva Chitongo-transformed peripheral blood mononuclear cells after in vitro infection. In the current study, infection experiments with WC1(+) γδ T cells revealed that only T. parva Muguga could infect these cells and that no transformed cells could be obtained with T. parva Chitongo sporozoites. Subsequent analysis of the susceptibility of different cell lines and purified populations of lymphocytes to infection and transformation by both isolates showed that T. parva Muguga sporozoites could attach to and infect CD4(+), CD8(+), and WC1(+) T lymphocytes, but T. parva Chitongo sporozoites were observed to bind only to the CD8(+) T cell population. Flow cytometry analysis of established, transformed clones confirmed this bias in target cells. T. parva Muguga-transformed clones consisted of different cell surface phenotypes, suggesting that they were derived from either host CD4(+), CD8(+), or WC1(+) T cells. In contrast, all in vitro and in vivo T. parva Chitongo-transformed clones expressed CD8 but not CD4 or WC1, suggesting that the T. parva Chitongo-transformed target cells were exclusively infected CD8(+) lymphocytes. Thus, a role of cell tropism in virulence is likely. Since the adhesion molecule p67 is 100% identical between the two strains, a second, high-affinity adhesin that determines target cell specificity appears to exist.
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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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Kishima M, Dolan TT, Njamunggeh RE, Nkonge CG, Spooner PR. Humoral immune responses to Theileria parva in cattle as measured by two-dimensional western blotting. Parasitol Res 1995; 81:334-42. [PMID: 7624293 DOI: 10.1007/bf00931541] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Humoral immune responses to schizont antigens from six stocks of Theileria parva were compared by two-dimensional Western blotting using sera from cattle that had been infected with a T. parva stock or a clone. Isoelectric points of a polymorphic immunodominant molecule (PIM) of schizonts that induces strong antibody responses in cattle ranged from acidic to basic. Molecular masses (Mr) of the PIM of the respective T. parva stocks were as follows: T. parva Muguga, 86 kDa; Mariakani, 83 kDa; Marikebuni, 83 kDa; Uganda, 83 kDa; T. parva Boleni, 83 kDa; and T. parva 7014, 100 kDa. Among nine cattle infected with T. parva Muguga, four produced antibodies to a basic antigen having an Mr of 32 kDa. The PIM of T. parva Muguga, T. parva Boleni, and T. parva 7014 reacted strongly with serum obtained from an animal that had been infected with T. parva Muguga. Two-dimensional Western blotting using antischizont monoclonal antibodies enabled us to differentiate between stocks of T. parva.
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Affiliation(s)
- M Kishima
- International Laboratory for Research on Animal Diseases, Nairobi, Kenya
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Bishop RP, Sohanpal BK, Allsopp BA, Spooner PR, Dolan TT, Morzaria SP. Detection of polymorphisms among Theileria parva stocks using repetitive, telomeric and ribosomal DNA probes and anti-schizont monoclonal antibodies. Parasitology 1993; 107 ( Pt 1):19-31. [PMID: 8102796 DOI: 10.1017/s0031182000079361] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A total of 21 Theileria parva stocks from 6 countries were characterized using T. parva repetitive and ribosomal DNA probes, a Plasmodium berghei telomeric oligonucleotide and a panel of anti-schizont monoclonal antibodies (MAbs). Hybridization of the repetitive DNA probe to Southern blots of EcoRI-digested T. parva DNA revealed 20 different restriction fragment patterns among DNA samples isolated from infections initiated using 16 parasite stocks. The panel of anti-schizont MAbs defined 8 different profiles among schizont-infected lymphoblastoid cell-cultures infected with the same 16 T. parva stocks. Many stocks, which were differentiated by the repetitive DNA probe, could not be distinguished using the anti-schizont MAbs. A cloned T. parva small subunit ribosomal RNA (SSUrRNA) gene probe separated 17 T. parva stocks into 2 groups, exhibiting either 1 or 2 restriction fragments, when hybridized to EcoRI-digested T. parva DNA. When hybridized to PvuII-digested DNA from 8 T. parva stocks, the ribosomal probe identified 4 groups with similar restriction fragment patterns. A synthetic oligonucleotide derived from a P. berghei telomeric sequence hybridized to 7 or 8 size-polymorphic restriction fragments in the EcoRI-digested DNA of most T. parva stocks. The telomeric and ribosomal probes defined the same 4 groups among 8 T. parva stocks as assessed by similarities in restriction fragment patterns. Based on the comparison of repetitive DNA sequences from the T. parva Uganda and Muguga stocks, a synthetic oligonucleotide was developed which distinguished the DNA of the T. parva Uganda stock from that of 4 other T. parva stocks on a positive/negative basis.
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Affiliation(s)
- R P Bishop
- International Laboratory for Research on Animal Diseases, Nairobi, Kenya
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Conrad PA, Thomford JW, Marsh A, Telford SR, Anderson JF, Spielman A, Sabin EA, Yamane I, Persing DH. Ribosomal DNA probe for differentiation of Babesia microti and B. gibsoni isolates. J Clin Microbiol 1992; 30:1210-5. [PMID: 1349901 PMCID: PMC265252 DOI: 10.1128/jcm.30.5.1210-1215.1992] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The objective of this study was to determine whether different isolates of Babesia microti could be distinguished from morphologically similar isolates of B. gibsoni by using a ribosomal DNA (rDNA) probe. A Babesia-specific rDNA probe was obtained by polymerase chain reaction amplification of sequences from B. microti DNA using universal primers directed against highly conserved portions of the eukaryotic 16S-like rRNA gene. The chemiluminescent rDNA probe hybridized to Southern blots of restriction endonuclease-digested DNA preparations of different isolates of B. gibsoni from infected dogs and B. microti from infected humans and white-footed mice. Restriction fragment length polymorphisms served to differentiate these species. Although the hybridization patterns seen with DNAs from six B. microti isolates did not vary, those of the five B. gibsoni isolates did indicate genotypic variation. We concluded that isolates of B. microti and B. gibsoni can be differentiated on the basis of restriction fragment length polymorphism detected with a chemiluminescent rDNA probe.
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Affiliation(s)
- P A Conrad
- Department of Veterinary Microbiology and Immunology, University of California, Davis 95616
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Sugimoto C, Mutharia LM, Brown WC, Pearson TW, Dolan TT, Conrad PA. Analysis of Theileria parva immunodominant schizont surface antigen by two-dimensional polyacrylamide gel electrophoresis and immunoblotting. Parasitol Res 1992; 78:82-5. [PMID: 1584754 DOI: 10.1007/bf00936188] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- C Sugimoto
- National Institute of Animal Health, Ibaraki, Japan
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Toye PG, Goddeeris BM, Iams K, Musoke AJ, Morrison WI. Characterization of a polymorphic immunodominant molecule in sporozoites and schizonts of Theileria parva. Parasite Immunol 1991; 13:49-62. [PMID: 1901640 DOI: 10.1111/j.1365-3024.1991.tb00262.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This study examines several aspects of a polymorphic, immunodominant molecule (PIM) found in the protozoan parasite, Theileria parva. The antigen is present in all T.p. parva stocks examined, and in the related subspecies, T.p.bovis and T.p.lawrencei. It is the predominant antigen recognized by antisera from immune cattle on Western blot analysis of schizont-infected lymphocytes, and is the only antigen which has been shown to react with anti-schizont monoclonal antibodies (MoAbs) on Western blots or in immunoprecipitations. The antigen shows polymorphism in both size and expression of antibody epitopes among the different stocks of T. parva. The antigen is present in sporozoites as well as schizonts.
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Affiliation(s)
- P G Toye
- International Laboratory for Research on Animal Diseases, Nairobi, Kenya
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Chen PP, Conrad PA, ole-MoiYoi OK, Brown WC, Dolan TT. DNA probes detect Theileria parva in the salivary glands of Rhipicephalus appendiculatus ticks. Parasitol Res 1991; 77:590-4. [PMID: 1792229 DOI: 10.1007/bf00931019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The ability of Theileria parva-specific DNA probes to detect T. parva sporoblasts and sporozoites in samples prepared from the salivary glands of infected Rhipicephalus appendiculatus ticks was evaluated. The two DNA probes used, pgTpM-23 and IgTpM-58, were selected from a genomic library of T. parva (Muguga) piroplasm DNA. In all, 25-200 adult ticks infected with each of 6 different T. parva stocks were tested. One salivary gland from each tick was processed for DNA hybridization, whereas the other was stained and examined by light microscopy to determine the number of infected acini. The correlation for the detection of infected acini between the two methods was 90%-100% for both probes, except when the pgTpM-23 probe was hybridised to salivary glands from ticks infected with the Mariakani stock of T. parva (84% correlation). The discrepancy lay within the range expected, based on the observation that in 12.5% of the ticks, only one salivary gland was infected. The probes did not hybridize to salivary glands from uninfected ticks.
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Affiliation(s)
- P P Chen
- International Laboratory for Research on Animal Diseases (ILRAD), Nairobi, Kenya
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Brown WC, Sugimoto C, Grab DJ. Theileria parva: bovine helper T cell clones specific for both infected lymphocytes and schizont membrane antigens. Exp Parasitol 1989; 69:234-48. [PMID: 2529135 DOI: 10.1016/0014-4894(89)90070-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Two Theileria parva-specific bovine helper T cell clones were used to identify T. parva-derived antigens expressed on the surface of schizont infected lymphoblastoid cells. Although the clones proliferated in response to both the immunizing (Muguga) and heterologous stocks of T. parva, the patterns of the responses differed, showing that the two clones recognized different antigenic epitopes. Both clones were stimulated by autologous infected cells, without an additional source of antigen-presenting cells, as well as by purified schizonts and by a subcellular membrane fraction prepared from infected lymphoblastoid cells, when antigen-presenting cells were present. The membrane fraction was shown to be enriched for schizont membranes as indicated by the presence of a schizont surface antigen detected by immunoblotting using a schizont-specific monoclonal antibody. Elimination of schizonts with the anti-theilerial drug, parvaquone, resulted in reduced antigenicity of the membrane fraction as detected by both the T cell clones and the schizont-specific monoclonal antibody. We conclude that the T. parva-infected cell surface antigens recognized by the T cell clones are of schizont membrane origin. Although the antigens have not yet been characterized biochemically, the monoclonal antibody-specific epitope appears to be distinguishable from the T cell epitopes.
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Affiliation(s)
- W C Brown
- International Laboratory for Research on Animal Diseases, Nairobi, Kenya
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