Identification and characterisation of conserved epitopes of E. ruminantium that activate Th1 CD4+ T cells : towards the development of a multi-epitope vaccine
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Date
Authors
Thema, Nontobeko
Tshilwane, Selaelo Ivy
Pretorius, Alri
Son, L.
Smith, R.M.
Steyn, Helena C.
Liebenberg, Junita
Van Kleef, Mirinda
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Several studies have shown that cytotoxic T lymphocytes (CTL) require CD4 + Th1 epitopes to generate strong immune responses to intracellular pathogens. However, not much is known about Ehrlichia ruminantium epitopes, particularly those that can be considered potential candidates for inclusion in a multi-epitope vaccine. In order to identify CD4+ Th1 epitopes that induce IFNγ, a number of proteins previously identified as immunogenic were first screened to determine if they induce cellular immunity in tick infected immune sheep PBMC. Significant IFN-γ production and other Th1 cytokines were evident for 10 recombinant proteins in all sheep tested. Secondly, peptides (n = 246) derived from the top 10 E. ruminantium vaccine candidate proteins were assayed using enzyme linked immunospot (ELISPOT) assay, quantitative real-time PCR and flow cytometry. Of the 246 peptides, 23 peptides, Erum0660 (p0660-42), Erum1150 (p1150-18, p1150-19), Erum2540 (p2540-6, p2540-16, p2540-19, p2540-20, p2540-21), Erum5420 (p5420-13, p5420-14), Erum7140 (p7140-6, p7140-7, p7140-12, p7140-13, p7140-20), Erum7320 (p7320-8, p7320-9, p7320-21), Erum7350 (p7350-9), Erum7360 (p7360-8), Erum7620 (p7620-2, p7620-12) and Erum8010 (p8010-8) were identified that stimulate the best and different cell mediated immune responses. Amino acid sequences of these peptides except for p7140-12, p7140-13, p7140-20, and p7350-9 were conserved between 13 different local strains. These peptides could efficiently induce memory CD4+ T cells to rapidly proliferate and significantly increase IFN-γ production in immune sheep PBMC. The upregulation of pro-inflammatory cytokines, which include, IL-1α, IL-2, IL-12p40, TNF-α, IFN-γ, inducible nitric oxide synthase (iNOS) and granulocyte-macrophage colony stimulating factor (GM-CSF) was also detected. Our results show that these peptides could serve as promising candidates for a multi-epitope vaccine against E. ruminantium.
Description
Keywords
Cytotoxic T lymphocytes (CTL), Enzyme linked immunospot (ELISPOT), Ehrlichia ruminantium, Antigens, CD4+T cells, Peptides, Interferon gamma (IFNγ)
Sustainable Development Goals
Citation
Thema, N., Tshilwane, S.I., Pretorius, A. et al. 2019, 'Identification and characterisation of conserved epitopes of E. ruminantium that activate Th1 CD4+ T cells : towards the development of a multi-epitope vaccine', Molecular Immunology, vol. 107, pp. 106-114.