Association between Plasma Antibody Response and Protection in Rainbow Trout Oncorhynchus mykiss Immersion Vaccinated against Yersinia ruckeri

A key hallmark of the vertebrate adaptive immune system is the generation of antigen-specific antibodies from B cells. Fish are the most primitive gnathostomes (jawed vertebrates) possessing an adaptive immune system. Vaccination of rainbow trout against enteric redmouth disease (ERM) by immersion in Yersinia ruckeri bacterin confers a high degree of protection to the fish. The immune mechanisms responsible for protection may comprise both cellular and humoral elements but the role of specific immunoglobulins in this system has been questioned and not previously described. The present study demonstrates significant increase in plasma antibody titers following immersion vaccination and significantly reduced mortality during Y. ruckeri challenge

Transcriptional Responses of Resistant and Susceptible Fish Clones to the Bacterial Pathogen Flavobacterium psychrophilum

Flavobacterium psychrophilum is a bacterial species that represents one of the most important pathogens for aquaculture worldwide, especially for salmonids. To gain insights into the genetic basis of the natural resistance to F. psychrophilum, we selected homozygous clones of rainbow trout with contrasted susceptibility to the infection. We compared the transcriptional response to the bacteria in the pronephros of a susceptible and a resistant line by micro-array analysis five days after infection. While the basal transcriptome of healthy fish was significantly different in the resistant and susceptible lines, the transcriptome modifications induced by the bacteria involved essentially the same genes and pathways. The response to F. psychrophilum involved antimicrobial peptides, complement, and a number of enzymes and chemokines. The matrix metalloproteases mmp9 and mmp13 were among the most highly induced genes in both genetic backgrounds. Key genes of both pro- and anti-inflammatory response such as IL1 and IL10, were up-regulated with a greater magnitude in susceptible animals where the bacterial load was also much higher. While higher resistance to F. psychrophilum does not seem to be based on extensive differences in the orientation of the immune response, several genes including complement C3 showed stronger induction in the resistant fish. They may be important for the variation of susceptibility to the infection

Measurement of the differential cross sections for the associated production of a W boson and jets in proton-proton collisions at root s=13 TeV

Peer reviewe

Flow chart of the experimental setup.

<p>A total of 800 rainbow trout were divided into four groups each containing 200 fish. One group was immersion vaccinated with the experimental bacterin vaccine. Two groups were immersion-vaccinated with the commercial AquaVac™ ERM. One of these groups received an oral booster vaccination with AquaVac™ ERM Oral vet 16 weeks post vaccination. All vaccines were diluted 1∶10 in water, and the fish were immersed for 5 minutes. The control group was sham-immersion vaccinated in pure water. A subsample of 25 rainbow trout from each group were given a challenge with <i>Y. ruckeri</i> 8 and 26 weeks post vaccination to monitor protection. Ten fish from each group were killed and used for plasma sampling 4, 8, 12, 16, and 26 weeks post vaccination.</p

Bactericidal effect of rainbow trout plasma.

<p>The present experiment shows that plasma from sham vaccinated rainbow trout contains factors that are able to kill a significant amount of <i>Y. ruckeri</i> (A, p<0.01 and B) p<0.05. Further it is shown that plasma obtained from immersion vaccinated trout kill a significant higher amount of <i>Y. ruckeri</i> than plasma from sham-vaccinated trout. Bars represent mean values + SD values. * Depicts statistical significance between groups (*<i>P</i><0.05; **<i>P</i><0.01; ***<i>P</i><0.001).</p