CD8 T Cell Responses to an Immunodominant Epitope within the Nonstructural Protein NS1 Provide Wide Immunoprotection against Bluetongue Virus in IFNAR ^−/− Mice

Abstract

Conventional vaccines have controlled or limited BTV expansion in the past, but they cannot address the need for cross-protection among serotypes and do not allow distinguishing between infected and vaccinated animals (DIVA strategy). There is a need to develop universal vaccines that induce effective protection against multiple BTV serotypes. In this work we have shown the importance of the nonstructural protein NS1, conserved among all the BTV serotypes, in CD8 T cell-mediated protection against multiple BTV serotypes when vectorized as a recombinant MVA vaccine.

Inhibition of Orbivirus Replication by Aurintricarboxylic Acid

“…A Spanish isolate of AHSV serotype 4 (Madrid-87) was passaged twice in mouse brain and three times in BHK-21 [ 70 ]. Virus stocks were propagated in Vero cells and titrated by the plaque assay as previously described [ 27 , 28 , 71 ]. KC cells and BTV-4(M) were generously provided by Professor Peter Mertens (IAH-Pirbright, UK).…”

“…At 24 and 48 h.p.i. (Vero cells) or 48 and 72 h h.p.i (KC cells), aliquots of the tissue culture supernatants were collected and evaluated by the plaque assay as previously described [ 27 , 28 , 71 ]. Triplicate wells were used to calculate the mean and SD of the inhibition.…”

“…Vero cells (24-well plate format, 2 × 10 5 cells/well, triplicates) were incubated with the indicated concentrations of ATA during 24 or 48 h. Then, the cells were infected (MOI, 0.01) with BTV or AHSV, and after 90 min of incubation at 37 °C, the medium was removed, and 1 mL of fresh infectious medium was added to the cells. At 24 h, tissue culture supernatants were harvested and evaluated by the plaque assay [ 27 , 28 , 71 ].…”

“…Solutions were administrated once daily, during 8 days, and clinical signs of toxicity were monitored. After 3 and 7 days, blood samples were collected into EDTA tubes and evaluated using a multiparameter autohematology analyzer (BC-5300 Vet; Mindray, Shenzhen, China) [ 71 ].…”

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

“…Additionally, these vaccines target mostly protein VP2, which represents the main inductor of neutralizing antibodies but has a highly variable antigen sequence among serotypes (up to 72.9% aa divergence) [ 12 ]. These conventional vaccines have been useful to control or limit BTV expansion so far, but they are not suitable for cross-protection between serotypes and do not permit the differentiation between infected and vaccinated animals (DIVA strategy) [ 14 , 15 ]. Non-structural proteins have been found to play a key role in several aspects of the infection such as virulence and replication and have therefore been studied as targets for antiviral therapies [ 16 , 17 ].…”