Location: Cool and Cold Water Aquaculture Research
Title: Transfer of serum and cells from Yersinia ruckeri vaccinated double-haploid Hot Creek Rainbow trout into outcross F1 progeny elucidates mechanisms of vaccine-induced protection Authors
Submitted to: Developmental and Comparative Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 4, 2013
Publication Date: December 14, 2013
Citation: Evenhuis, J., Wiens, G.D., Wheeler, P., Welch, T.J., Lapatra, S.E., Thorgaard, G. 2013. Transfer of serum and cells from Yersinia ruckeri vaccinated double-haploid Hot Creek Rainbow trout into outcross F1 progeny elucidates mechanisms of vaccine-induced protection. Developmental and Comparative Immunology. 44: 145-151. DOI: 10.1016/j.dci.2013.12.004. Interpretive Summary: The vaccine for enteric red mouth disease (ERM) in rainbow trout has been effective at eliminating losses but the productive immune mechanism stimulated by this vaccine has not been adequately explained. We show that the circulating IgM antibodies, and not the circulating white blood cells, are the long term protective component of the immune system that is stimulated by the vaccine. Transferring plasma, in volumes as low as 0.5 microliters, from vaccinated rainbow trout to naive recipients completely protects the recipients when challenged with the bacterium responsible for ERM.
Technical Abstract: Yersinia ruckeri is a well-established bacterial pathogen for many salmonid species, against which a formalin-killed bacterin vaccine has been effective in reducing disease outbreaks. Previous studies have reported conflicting results about the protective value of the circulating humoral response to Yersinia ruckeri vaccination. Here we directly demonstrate that circulating plasma is the long-term protective component elicited by both immersion and intraperitoneal injection vaccination of rainbow trout. A total of 0.5 microliters of vaccinated sera provided a high level of protection against experimental challenge. The circulating cells obtained from peripheral blood, conferred little or no protection in naïve recipients. The protective component of immune sera was IgM based on size exclusion chromatography and recognition by monoclonal antibody 1-14. Immune plasma generated against a Y. ruckeri biotype 1 strain protected equally against Y. ruckeri biotype 1 and 2 challenges. These results illustrate the importance of the humoral IgM response against Y. ruckeri and the use of double haploid rainbow trout and adoptive transfer of serum and cells into F1 outcross progeny as a model system for dissection of the mechanisms of vaccine-induced protection.