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Faber E, van Schalkwyk A, Ivy Tshilwane S, Van Kleef M, Pretorius A. Identification of T cell and linear B cell epitopes on African horse sickness virus serotype 4 proteins VP1-1, VP2, VP4, VP7 and NS3. Vaccine 2024; 42:136-145. [PMID: 38097459 DOI: 10.1016/j.vaccine.2023.12.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/30/2023] [Accepted: 12/06/2023] [Indexed: 01/01/2024]
Abstract
The viral proteins VP1-1, VP2, VP4, VP7 and NS3, of African horse sickness virus serotype 4 (AHSV4), have previously been identified to contain CD8+ T cell epitopes. In this study, overlapping peptides spanning the entire sequences of these AHSV4 proteins were synthesized and used to map epitopes. Peripheral blood mononuclear cells (PBMC) isolated from five horses immunized with an attenuated AHSV4 were stimulated in vitro with the synthesized peptides. Various memory immune assays were used to identify the individual peptides that contain CD8+ T cell epitopes, CD4+ T cell epitopes and linear B cell epitopes. The newly discovered individual peptides of AHSV4 proteins VP1-1, VP4, VP7 and/or NS3 that contain CD8+ T cell, CD4+ T cell or linear B cell epitopes could contribute to the design and development of new generation AHS peptide-based vaccines and therapeutics.
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Affiliation(s)
- Erika Faber
- Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort 0110, South Africa.
| | - Antoinette van Schalkwyk
- Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort 0110, South Africa; Department of Biotechnology, University of the Western Cape, Robert Sobukwe road, Bellville 7535, South Africa
| | - Selaelo Ivy Tshilwane
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Mirinda Van Kleef
- Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort 0110, South Africa; Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Alri Pretorius
- Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort 0110, South Africa; Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
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Tjale MA, Liebenberg J, Steyn H, Van Kleef M, Pretorius A. Transcriptome analysis of Ehrlichia ruminantium in the ruminant host at the tick bite site and in the tick vector salivary glands. Ticks Tick Borne Dis 2020; 12:101646. [PMID: 33508537 DOI: 10.1016/j.ttbdis.2020.101646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 10/22/2022]
Abstract
Heartwater is a non-contagious tick-borne disease of domestic and wild ruminants. Data regarding the complex processes involved during pathogen-vector-host interaction during Ehrlichia ruminantium infection is lacking and could be improved with knowledge associated with gene expression changes in both the pathogen and the host. Thus, in the current study, we aimed to identify E. ruminantium genes that are up-regulated when the pathogen enters the host and before the disease is established. Identification of such genes/proteins may aid in future vaccine development strategies against heartwater. RNA-sequencing was used to identify E. ruminantium genes that were exclusively expressed at the tick bite site in sheep skin biopsies (SB) and in adult tick salivary glands (SG). RNA was extracted from pooled samples of the SB or SG collected at different time points during tick attachment and prior to disease manifestation. Ribosomal RNA (rRNA) was removed and the samples were sequenced. Several E. ruminantium genes were highly expressed in all the samples while others were exclusively expressed in each. It was concluded that E. ruminantium genes that were exclusively expressed in the SB or both SB and SG when compared to the transcriptome datasets from bovine elementary bodies (BovEBs) from cell culture may be considered as early antigenic targets of host immunity. In silico immunogenic epitope prediction analysis and preliminary characterization of selected genes in vitro using ELIspot assay showed that they could possibly be ideal targets for future vaccine development against heartwater, however, further epitope characterization is still required.
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Affiliation(s)
- Mabotse A Tjale
- Department of Veterinary Tropical Disease, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa; Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort 0110, South Africa.
| | - Junita Liebenberg
- Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort 0110, South Africa
| | - Helena Steyn
- Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort 0110, South Africa
| | - Mirinda Van Kleef
- Department of Veterinary Tropical Disease, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa; Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort 0110, South Africa
| | - Alri Pretorius
- Department of Veterinary Tropical Disease, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa; Agricultural Research Council - Onderstepoort Veterinary Research, Private Bag X5, Onderstepoort 0110, South Africa
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Thema N, Tshilwane S, Pretorius A, Son L, Smith R, Steyn H, Liebenberg J, van Kleef M. Identification and characterisation of conserved epitopes of E. ruminantium that activate Th1 CD4+ T cells: Towards the development of a multi-epitope vaccine. Mol Immunol 2019; 107:106-114. [DOI: 10.1016/j.molimm.2018.12.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 11/06/2018] [Accepted: 12/09/2018] [Indexed: 01/21/2023]
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Thema N, Pretorius A, Tshilwane SI, Liebenberg J, Steyn H, Van Kleef M. Cellular immune responses induced <i>in vitro</i> by <i>Ehrlichia ruminantium</i> secreted proteins and identification of vaccine candidate peptides. ACTA ACUST UNITED AC 2016; 83:e1-e11. [PMID: 27608502 PMCID: PMC6238801 DOI: 10.4102/ojvr.v83i1.1170] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/12/2016] [Accepted: 04/14/2016] [Indexed: 01/01/2023]
Abstract
Secreted proteins are reported to induce cell-mediated immunity characterised by the production of interferon-gamma (IFN)-γ. In this study three open reading frames (ORFs) (Erum8060, Erum7760, Erum5000) encoding secreted proteins were selected from the Ehrlichia ruminantium (Welgevonden) genome sequence using bioinformatics tools to determine whether they induce a cellular immune response in vitro with mononuclear cells from needle and tick infected animals. The whole recombinant protein of the three ORFs as well as four adjacent fragments of the Erum5000 protein (Erum5000A, Erum5000B, Erum5000C, Erum5000D) were successfully expressed in a bacterial expression system which was confirmed by immunoblots using anti-His antibodies and sheep sera. These recombinant proteins were assayed with immune sheep and cattle peripheral blood mononuclear cells (PBMCs), spleen and lymph node (LN) cells to determine whether they induce recall cellular immune responses in vitro. Significant proliferative responses and IFN-γ production were evident for all recombinant proteins, especially Erum5000A, in both ruminant species tested. Thus overlapping peptides spanning Erum5000A were synthesised and peptides that induce proliferation of memory CD4+ and CD8+ T cells and production of IFN-γ were identified. These results illustrate that a Th1 type immune response was elicited and these recombinant proteins and peptides may therefore be promising candidates for development of a heartwater vaccine.
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Affiliation(s)
- Nontobeko Thema
- New Generation Vaccines Programme, Agricultural Research Council-Onderstepoort Veterinary Institute; Department of Veterinary Tropical Diseases, University of Pretoria.
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Sebatjane S, Pretorius A, Liebenberg J, Steyn H, Van Kleef M. In vitro and in vivo evaluation of five low molecular weight proteins of Ehrlichia ruminantium as potential vaccine components. Vet Immunol Immunopathol 2010; 137:217-25. [DOI: 10.1016/j.vetimm.2010.05.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 05/13/2010] [Accepted: 05/26/2010] [Indexed: 11/24/2022]
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Pretorius A, Collins NE, Steyn HC, van Strijp F, van Kleef M, Allsopp BA. Protection against heartwater by DNA immunisation with four Ehrlichia ruminantium open reading frames. Vaccine 2007; 25:2316-24. [PMID: 17224211 DOI: 10.1016/j.vaccine.2006.11.061] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 11/22/2006] [Accepted: 11/28/2006] [Indexed: 11/22/2022]
Abstract
We have reported previously that a recombinant DNA vaccine consisting of four Ehrlichia ruminantium (Welgevonden) open reading frames (ORFs) known as the 1H12 cocktail provided protection against a virulent E. ruminantium (Welgevonden) needle challenge in sheep. In this study, we have investigated the vaccine effectiveness of two other cocktails of E. ruminantium (Welgevonden) ORFs, as well as single ORFs from the 1H12 cocktail, to protect sheep against a virulent needle challenge with the homologous strain. Each individual 1H12 ORF provided protection, but all the animals vaccinated with the other cocktails succumbed to the challenge.
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Affiliation(s)
- A Pretorius
- Onderstepoort Veterinary Institute, Private Bag X5, Onderstepoort 0110, South Africa.
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Wallace DB, Viljoen GJ. Immune responses to recombinants of the South African vaccine strain of lumpy skin disease virus generated by using thymidine kinase gene insertion. Vaccine 2005; 23:3061-7. [PMID: 15811653 DOI: 10.1016/j.vaccine.2004.10.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Accepted: 10/11/2004] [Indexed: 11/21/2022]
Abstract
The South African vaccine strain of lumpy skin disease virus (type SA-Neethling) is currently being developed as a vector for recombinant vaccines of economically important livestock diseases throughout Africa. In this study, the feasibility of using the viral thymidine kinase gene as the site of insertion was investigated and recombinant viruses were evaluated in animal trials. Two separate recombinants were generated and selected for homogeneity expressing either the structural glycoprotein gene of bovine ephemeral fever virus (BEFV) or the two structural glycoprotein genes of Rift Valley fever virus (RVFV). Both recombinants incorporate the enhanced green fluorescent protein (EGFP) as a visual marker and the Escherichia coli guanine phosphoribosyl transferase (gpt) gene for dominant positive selection. The LSDV-RVFV recombinant construct (rLSDV-RVFV) protected mice against virulent RVFV challenge. In a small-scale BEFV-challenge cattle trial the rLSDV-BEFV construct failed to fully protect the cattle against virulent challenge, although both a humoral and cellular BEFV-specific immune response was elicited.
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Affiliation(s)
- David B Wallace
- Biotechnology Division, Onderstepoort Veterinary Institute, P/Bag X5, Onderstepoort 0110, South Africa.
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Abstract
To identify novel antigens with immunoglobulin G2 (IgG2) specificity and immunostimulant properties for bovine Th1 cells, humoral and cellular responses were studied in cattle inoculated with initial bodies from a Mexican isolate of Anaplasma marginale and challenged with a heterologous strain. Analysis of post-immunization sera by ELISA and assaying of in vitro cellular responses in peripheral blood mononuclear cells (PBMCs) cultured in the presence of protein extracts from three Anaplasma marginale strains showed positive values of optical density ELISA readings and stimulation indices in the immunized but not control cattle. Post-immunization and post-challenge sera recognized in Western blots several proteins with molecular weights ranging from 15 to 209 kDa, twelve of which were recognized by IgG2 in the three Anaplasma marginale strains. Seven of these are novel and have not been previously reported for their IgG2 specificity; three are confirmed to be major surface proteins (MSP-1a, MSP-2, and MSP-5); and the others correspond to other well-studied MSPs but were not confirmed. Partially purified fractions of protein extracts of the Mex-17 strain were tested against PBMCs cultured in vitro. One out of the seven novel proteins induced detectable lymphoproliferation (LP) of PBMCs, and interferon-gamma was detected in supernatants of PBMC cultured in the presence of two protein fractions, including the one that caused LP. It is concluded that novel antigens, particularly the 28-kDa protein, played an additional role in the protection of immunized cattle and should be considered vaccine candidates after in vivo immunization experiments are concluded.
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Affiliation(s)
- R Barigye
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Col. Coyoacán, Mexico D.F., Mexico
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Esteves I, Vachiéry N, Martinez D, Totté P. Analysis of Ehrlichia ruminantium-specific T1/T2 responses during vaccination with a protective killed vaccine and challenge of goats. Parasite Immunol 2004; 26:95-103. [PMID: 15225296 DOI: 10.1111/j.0141-9838.2004.00688.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ehrlichia ruminantium is an obligate intracellular bacterium that causes heartwater in ruminants and for which T-cell-mediated immunity is believed to play an important role in protection. To better characterize protective cellular immunity, E. ruminantium-specific IFN-gamma and IL-4 recall responses in major T-cell subsets were analysed by flow cytometry during immunization of goats with a killed vaccine and following a virulent challenge. The killed vaccine elicited both CD8+ and CD4+ subsets to produce cytoplasmic IFN-gamma in the absence of IL-4, thus indicating a biased T1 response. The relative capacity of CD8+ T-cells to produce IFN-gamma was significantly higher than CD4+ T-cells but the final contribution of both subsets was comparable. Circulating ER-specific CD4 and CD8 effectors substantially decreased in numbers after the booster injection and could not be detected in most animals during challenge, which warrants further investigation in immune compartments other than blood. Since IFN-gamma inhibits the growth of the pathogen in target cells, the information provided in this study on E. ruminantium-specific T1 responses will be valuable to develop cellular tools for the identification of potential protective antigens.
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Gunter N, Esteves I, Kandassamy Y, Martinez D, Bensaid A, Van Kleef M, Du Plessis D, Totte P. Cowdria ruminantium antigens of around 15 kDa are potent inducers of IFN-gamma. Ann N Y Acad Sci 2002; 969:135-40. [PMID: 12381578 DOI: 10.1111/j.1749-6632.2002.tb04365.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cellular responses induced in two Creole goats by vaccination with killed Cowdria ruminantium (Cowdria) were confirmed by IFN-gamma production and interleukin-2 receptor (IL-2R) expression. Both CD4+ and CD8+ but not WC1+ T cells showed a substantial increase in cell surface expression of IL-2R molecules in response to whole Cowdria lysate. Cowdria (Welgevonden strain) proteins were fractionated using continuous-flow electrophoresis and tested for their ability to induce IFN-gamma production by PBMC collected three weeks after the first inoculation and one week after the booster injection. Pooled fractions of around 15, 22, and 24 kDa were found to induce significant IFN-gamma production in both vaccinated animals on one of the two occasions. Antigens of around 15 kDa induced substantially higher IFN-gamma production than any other fractions in both animals. These pilot experiments pave the way towards the identification of proteins/genes that have potential for the development of a recombinant vaccine against heartwater.
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Affiliation(s)
- N Gunter
- Department of Immunology, Onderstepoort Veterinary Institute, Onderstepoort, Republic of South Africa
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Barbet AF, Whitmire WM, Kamper SM, Simbi BH, Ganta RR, Moreland AL, Mwangi DM, McGuire TC, Mahan SM. A subset of Cowdria ruminantium genes important for immune recognition and protection. Gene 2001; 275:287-98. [PMID: 11587856 DOI: 10.1016/s0378-1119(01)00682-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cowdria ruminantium causes the tick-borne rickettsial disease of heartwater, which is devastating to livestock production in sub-Saharan Africa. Current diagnosis and control methods are inadequate. We have identified and sequenced a subset of genes encoding recombinant antigens recognized by antibody and peripheral blood mononuclear cells from immune ruminants. The identified genes include many with significant similarity to those of Rickettsia prowazekii, genes predicted to encode different outer membrane proteins and lipoproteins and a gene containing an unusual tandem repeat structure. Evidence is presented for immune protection by recombinant antigens in a mouse model of C. ruminantium infection. These data identify new recombinant antigens for evaluation in vaccines and diagnostic tests to control heartwater.
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Affiliation(s)
- A F Barbet
- Department of Pathobiology, University of Florida, Gainesville, FL, USA.
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