Long-term efficacy of nasal vaccination against enteric red mouth (ERM) disease and infectious hematopoietic necrosis (IHN) in juvenile rainbow trout (Oncorhynchus mykiss)

Jie Ma; Elisa Casadei; Timothy J Bruce; Ali Sepahi; Kenneth D Cain; Irene Salinas

doi:10.1016/j.vaccine.2021.11.077

Long-term efficacy of nasal vaccination against enteric red mouth (ERM) disease and infectious hematopoietic necrosis (IHN) in juvenile rainbow trout (Oncorhynchus mykiss)

Vaccine. 2022 Jan 21;40(2):229-238. doi: 10.1016/j.vaccine.2021.11.077. Epub 2021 Dec 7.

Authors

Jie Ma¹, Elisa Casadei², Timothy J Bruce¹, Ali Sepahi², Kenneth D Cain³, Irene Salinas⁴

Affiliations

¹ University of Idaho, Department of Fish and Wildlife Sciences, 875 Perimeter Dr. MS1136, Moscow, ID 83844, United States.
² Center for Evolutionary and Theoretical Immunology, Biology Department, University of New Mexico, Albuquerque, New Mexico, USA.
³ University of Idaho, Department of Fish and Wildlife Sciences, 875 Perimeter Dr. MS1136, Moscow, ID 83844, United States. Electronic address: kcain@uidaho.edu.
⁴ Center for Evolutionary and Theoretical Immunology, Biology Department, University of New Mexico, Albuquerque, New Mexico, USA. Electronic address: isalinas@unm.edu.

PMID: 34893343
DOI: 10.1016/j.vaccine.2021.11.077

Abstract

Previous research demonstrated that bacterial and viral vaccines delivered via the nasal route in rainbow trout (Oncorhynchus mykiss) at 7 and 28 days post-vaccination are highly protective (>95% protection). Long-term protection following nasal vaccination in teleosts has not been evaluated. The goal of this study was to assess efficacy and immune responses at 6 months (mo) post-vaccination (mpv), and long-lasting immune responses at 12 mpv of two different vaccines: an inactivated enteric red mouth disease (ERM) Yersinia ruckeri bacterin and a live attenuated infectious hematopoietic necrosis virus (IHNV) vaccine. Juvenile rainbow trout were vaccinated for Y. ruckeri via intraperitoneal (I.P.) and intranasal (I.N.) routes, and for IHNV by intramuscular (I.M.) and I.N. routes, then challenged at 6 mpv. Immune responses were determined at 6 and 12 mpv. ERM vaccine I.P. delivery elicited significantly higher serum IgM-specific titers that remained elevated compared to mock-vaccinated fish at 6 mpv. By 12 mpv, antibody titers to Y. ruckeri were not significantly different across all treatments. Following Y. ruckeri challenge at 6 mpv, a significant difference in cumulative percent mortality (CPM) was found for I.P.-vaccinated fish but not I.N.-vaccinated fish. I.M. and I.N. vaccination with live attenuated IHNV did not result in significant specific serum IgM titers at 6 or 12 mpv. Yet, I.N.-vaccinated fish showed the lowest CPM 6 mpv indicating long-term protection that does not correlate with systemic IgM responses. Repertoire analyses confirmed unique expansions of VH-JH rearrangements in the spleen of rainbow trout 12 mpv that varied with the type of vaccine and route of vaccination. Combined, these data demonstrate that I.N. vaccination with a live attenuated viral vaccine confers long lasting protection, but I.N. ERM vaccination does not and booster before 6 mpv is recommended.

Keywords: Aquaculture; ERM; IHNV; Long-term protection; Nasal vaccines; Rainbow trout; Repertoire.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Animals
Fish Diseases* / prevention & control
Mouth Diseases*
Necrosis
Oncorhynchus mykiss*
Vaccination
Yersinia Infections* / prevention & control
Yersinia Infections* / veterinary
Yersinia ruckeri