An Integrated in silico and in vivo study of nucleic acid vaccine against Nocardia seriolae infection in orange-spotted grouper Epinephelus coioides

Phuong T D Nguyen; Andre Giovanni; Shun Maekawa; Trung Hieu Pham; Pei-Chi Wang; Shih-Chu Chen

doi:10.1016/j.fsi.2023.109202

An Integrated in silico and in vivo study of nucleic acid vaccine against Nocardia seriolae infection in orange-spotted grouper Epinephelus coioides

Fish Shellfish Immunol. 2023 Dec:143:109202. doi: 10.1016/j.fsi.2023.109202. Epub 2023 Oct 31.

Authors

Phuong T D Nguyen¹, Andre Giovanni², Shun Maekawa³, Trung Hieu Pham⁴, Pei-Chi Wang⁵, Shih-Chu Chen⁶

Affiliations

¹ International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan. Electronic address: nguyendiemphuong@gmail.com.
² International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan. Electronic address: andregio7796@gmail.com.
³ International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan; Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan; General Research Service Centre, National Pingtung University of Science and Technology, Pingtung, Taiwan. Electronic address: shun84topaz04@gmail.com.
⁴ International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan. Electronic address: trungsimap1985@yahoo.com.
⁵ Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan; Southern Taiwan Fish Diseases Research Centre, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan. Electronic address: pc921003@gmail.com.
⁶ International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Pingtung, Taiwan; Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan; Southern Taiwan Fish Diseases Research Centre, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan. Electronic address: scchen@mail.npust.edu.tw.

PMID: 37913891
DOI: 10.1016/j.fsi.2023.109202

Abstract

Nocardiosis in aquatic animals caused by Nocardia seriolae is a frequently occurring serious infection that has recently spread to many countries. In this study, DNA vaccines containing potential bacterial antigens predicted using the reverse vaccinology approach were developed and evaluated in orange-spotted groupers. In silico analysis indicated that proteins including cholesterol oxidase, ld-transpeptidase, and glycosyl hydroxylase have high immunogenicity and are potential vaccine candidates. In vitro assays revealed the mature and biological configurations of these proteins. Importantly, when compared to a control PBS injection, N. seriolae DNA-based vaccines showed significantly higher expression of IL1β, IL17, and IFNγ at 1 or 2 days, in line with higher serum antibody production and expression of other cellular immune-related genes, such as MHCI, CD4, and CD8, at 7 days post-immunization. Remarkably, enhanced immune responses and strong protective efficacy against a highly virulent strain of N. seriolae were recorded in DNA vaccine-cholesterol oxidase (pcD::Cho) injected fish, with a relative survival rate of 73.3%. Our results demonstrate that the reverse vaccinology approach is a valid strategy for screening vaccine candidates and pcD::Cho is a promising candidate that can boost both innate and adaptive immune responses and confer considerable protection against N. seriolae infection.

Keywords: DNA vaccine; In silico; Nocardia seriolae; Orange-spotted grouper; Vaxign-ML.

MeSH terms

Animals
Bass*
Cholesterol Oxidase
Fish Diseases*
Nocardia Infections* / prevention & control
Nocardia Infections* / veterinary
Nucleic Acid-Based Vaccines
Vaccines, DNA*

Substances

Nucleic Acid-Based Vaccines
Cholesterol Oxidase
Vaccines, DNA

Supplementary concepts

Nocardia seriolae