Ovine and murine T cell epitopes from the non-structural protein 1 (NS1) of bluetongue virus serotype 8 (BTV-8) are shared among viral serotypes

Abstract

Bluetongue virus (BTV) is a non-enveloped dsRNA virus that causes a haemorrhagic disease mainly in sheep. It is an economically important Orbivirus of the Reoviridae family. In order to estimate the importance of T cell responses during BTV infection, it is essential to identify the epitopes targeted by the immune system. In the present work, we selected potential T cell epitopes (3 MHC-class II-binding and 8 MHC-class I binding peptides) for the C57BL/6 mouse strain from the BTV-8 non-structural protein NS1, using H2b-binding predictive algorithms. Peptide binding assays confirmed all MHC-class I predicted peptides bound MHC-class I molecules. The immunogenicity of these 11 predicted peptides was then determined using splenocytes from BTV-8-inoculated C57BL/6 mice. Four MHC-class I binding peptides elicited specific IFN-γ production and generated cytotoxic T lymphocytes (CTL) in BTV-8 infected mice. CTL specific for 2 of these peptides were also able to recognise target cells infected with different BTV serotypes. Similarly, using a combination of IFN-γ ELISPOT, intracellular cytokine staining and proliferation assays, two MHC-class II peptides were identified as CD4+ T cell epitopes in BTV-8 infected mice. Importantly, two peptides were also consistently immunogenic in sheep infected with BTV-8 using IFN-γ ELISPOT assays. Both of these peptides stimulated CD4+ T cells that cross-reacted with other BTV serotypes. The characterisation of these T cell epitopes can help develop vaccines protecting against a broad spectrum of BTV serotypes and differentiate infected from vaccinated animals.

Heterologous Combination of ChAdOx1 and MVA Vectors Expressing Protein NS1 as Vaccination Strategy to Induce Durable and Cross-Protective CD8+ T Cell Immunity to Bluetongue Virus

“…The importance of the non-structural protein NS1 in CD8+ T cell-mediated protection against BTV has been previously showed [ 14 , 18 , 19 ]. Additionally, the NS1 protein is highly conserved among different BTV serotypes and so are the epitopes associated with T-cell responses [ 14 , 19 , 44 , 60 ]. Animals immunized with ChAdOx1-NS1 or ChAdOx1/MVA-NS1 were not only protected against infection with BTV-4(M) but also against a lethal dose of BTV-8.…”

“…Among them, NS1 is the most abundantly viral protein produced in infected cells. This protein contains epitopes related with T-cell-mediated responses which may play a major role in protection against BTV [ 18 , 19 ]. Further, its amino acid sequence is highly conserved among serotypes [ 20 , 21 ] which makes it a clear candidate for the development of universal multiserotype vaccines.…”

Vaccination with recombinant adenovirus expressing peste des petits ruminants virus-F or -H proteins elicits T cell responses to epitopes that arises during PPRV infection

“…PPRV vaccine strain Nigeria 1975/1 (PPRV Nig’75; lineage II) and PPRV infective strain Ivory Coast 1989 (PPRV IC’89; lineage I) were kindly provided by Dr Batten (IAH, Pirbright, UK). PPRV stocks were grown in VDS cells, purified as described in [ 16 ], and inactivated as described in [ 33 ]. Replication-defective recombinant adenovirus 5 construction expressing the F (Ad5-F) or H (Ad5-H) gene from PPRV Nig’75 vaccine strain is described [ 16 ].…”

“…Clinical details of vaccination results are reported in [ 23 ]. PBMC were prepared [ 33 ] and stored frozen until use. For in vitro peptide expansion, PBMC were thawed, rested for 2 h, stimulated with 10 µg/mL peptide for 6–7 days, washed and then used in functional assays.…”

Adenovirus as Tools in Animal Health

“…This can be very useful for vaccine design, and inclusion of genes targeted by cell-mediated immunity could improve immunogenicity [57,64]. Cell-mediated immunity can target epitopes encoded by conserved genes and thereby recognize infected cells independently of the virus serotype [65]. This could potentially provide some degree of protection against heterologous serotypes [66] in diseases like FMDV, IAV, or BTV in which cross-protection between serotypes is very limited.…”