An attenuated herpesvirus vectored vaccine candidate induces T-cell responses against highly conserved porcine reproductive and respiratory syndrome virus M and NSP5 proteins that are unable to control infection

Frontiers in Immunology

Immunology

Michael J. Francis¹  Beatriz Sanz-Bernardo²  Veronica L. Fowler²  Hafid Benchaoui²  Michael Huether²  Nicolás M. Suárez³  Andrew J. Davison³  Fabian Z. X. Lean⁴  Alejandro Nunez⁴  Matthieu Bernard⁴  Kerry Holtham⁵  Rory C. F. de Brito⁵  Simon Gubbins⁵  Simon P. Graham⁵  Jack E. Saunders⁶  Jessica Roser⁷  Summer Henderson⁷  Thekla Mauch⁷  Jeremy Salt⁷  Yvonne Wezel⁷  Michael A. Jarvis⁸  Jean-Pierre Frossard⁹ 

[1] BioVacc Consulting Ltd., Amersham, United Kingdom;ECO Animal Health, London, United Kingdom;MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom;Pathology and Animal Sciences Department, Animal and Plant Health Agency, Addlestone, United Kingdom;The Pirbright Institute, Woking, United Kingdom;The Pirbright Institute, Woking, United Kingdom;Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom;The Vaccine Group Ltd., Plymouth, United Kingdom;The Vaccine Group Ltd., Plymouth, United Kingdom;School of Biomedical Sciences, University of Plymouth, Plymouth, United Kingdom;Virology Department, Animal and Plant Health Agency, Addlestone, United Kingdom;

关键词: porcine reproductive and respiratory syndrome virus;    T cell;    vaccine;    bovine herpesvirus 4;    immunogenicity;    protective efficacy;   

DOI  :  10.3389/fimmu.2023.1201973

 received in 2023-04-07, accepted in 2023-07-14,  发布年份 2023

来源: Frontiers

【 摘 要 】

Porcine reproductive and respiratory syndrome virus (PRRSV) remains a leading cause of economic loss in pig farming worldwide. Existing commercial vaccines, all based on modified live or inactivated PRRSV, fail to provide effective immunity against the highly diverse circulating strains of both PRRSV-1 and PRRSV-2. Therefore, there is an urgent need to develop more effective and broadly active PRRSV vaccines. In the absence of neutralizing antibodies, T cells are thought to play a central role in controlling PRRSV infection. Herpesvirus-based vectors are novel vaccine platforms capable of inducing high levels of T cells against encoded heterologous antigens. Therefore, the aim of this study was to assess the immunogenicity and efficacy of an attenuated herpesvirus-based vector (bovine herpesvirus-4; BoHV-4) expressing a fusion protein comprising two well-characterized PRRSV-1 T-cell antigens (M and NSP5). Prime-boost immunization of pigs with BoHV-4 expressing the M and NSP5 fusion protein (vector designated BoHV-4-M-NSP5) induced strong IFN-γ responses, as assessed by ELISpot assays of peripheral blood mononuclear cells (PBMC) stimulated with a pool of peptides representing PRRSV-1 M and NSP5. The responses were closely mirrored by spontaneous IFN-γ release from unstimulated cells, albeit at lower levels. A lower frequency of M and NSP5 specific IFN-γ responding cells was induced following a single dose of BoHV-4-M-NSP5 vector. Restimulation using M and NSP5 peptides from PRRSV-2 demonstrated a high level of cross-reactivity. Vaccination with BoHV-4-M-NSP5 did not affect viral loads in either the blood or lungs following challenge with the two heterologous PRRSV-1 strains. However, the BoHV-4-M-NSP5 prime-boost vaccination showed a marked trend toward reduced lung pathology following PRRSV-1 challenge. The limited effect of T cells on PRRSV-1 viral load was further examined by analyzing local and circulating T-cell responses using intracellular cytokine staining and proliferation assays. The results from this study suggest that vaccine-primed T-cell responses may have helped in the control of PRRSV-1 associated tissue damage, but had a minimal, if any, effect on controlling PRRSV-1 viral loads. Together, these results indicate that future efforts to develop effective PRRSV vaccines should focus on achieving a balanced T-cell and antibody response.

【 授权许可】

Unknown   
Copyright © 2023 de Brito, Holtham, Roser, Saunders, Wezel, Henderson, Mauch, Sanz-Bernardo, Frossard, Bernard, Lean, Nunez, Gubbins, Suárez, Davison, Francis, Huether, Benchaoui, Salt, Fowler, Jarvis and Graham