Attempts at validating a recombinantFlavobacterium psychrophilumgliding motility protein N as a vaccine candidate in rainbow trout,Oncorhynchus mykiss(Walbaum) against bacterial cold-water disease

Abstract

The Flavobacterium psychrophilum gliding motility N (GldN) protein was investigated to determine its ability to elicit antibody responses and provide protective immunity in rainbow trout Oncorhynchus mykiss (Walbaum). GldN was PCR-amplified, cloned into pET102/D-TOPO, and expressed in Escherichia coli. Bacteria expressing recombinant GldN (rGldN) were formalin-inactivated and injected intraperitoneally (i.p.) into rainbow trout with Freund's complete adjuvant (FCA) in four separate studies that used two different immunization protocols followed by challenge evaluations. Fish injected with E. coli only in FCA served as the control. Antibody responses to F. psychrophilum whole-cell lysates measured by ELISA were low in all four studies. Protection against F. psychrophilum challenge was observed in the first study, but not in the three following studies. The discrepancies in results obtained in the later studies are unclear but may relate to formalin treatment of the antigen preparations. Overall, it appeared that rGldN delivered i.p. as a crude formalin-killed preparation is not a consistent vaccine candidate, and more work is required. Additionally, this study illustrates the importance of conducting multiple in vivo evaluations on potential vaccine(s) before any conclusions are drawn.

Quantitative trait loci for resistance to Flavobacterium psychrophilum in rainbow trout: effect of the mode of infection and evidence of epistatic interactions

“…It causes high mortalities (up to 70%) and deformities may occur in surviving fish [ 1 , 2 , 4 ], with important economic impacts. In spite of intensive research to develop efficient vaccines [ 5 – 7 ] and the recent commercialisation of a vaccine in some countries (ALPHA JECT ® IPNV-Flavo 0.025 PHARMAQ), the usual way to combat the disease remains the use of antibiotic treatments, which raises environmental concerns and issues about the emergence of antibiotic resistance [ 8 – 10 ]. Therefore, there is a crucial need for other methods to control the disease.…”

A Novel Efficient Piscine Oral Nano-Vaccine Delivery System: Modified Halloysite Nanotubes (HNTs) Preventing Streptococcosis Disease in Tilapia (Oreochromis sp.)

“…Unfortunately, the proteins of our bivalent vaccine (formalin-killed cells– S. agalactiae ) were invisible in SDS-PAGE analysis, which was similar to the FKC- E. coli , but some antigenic proteins could be detected by Western blot analysis [ 53 ]. It may explain that, during inactivation by formalin in the vaccine preparation process, the bacterial proteins were denatured and fixed in their cell membranes; consequently, protein contents were retained in the bacterial cell structures [ 54 ].…”

“…It may explain that, during inactivation by formalin in the vaccine preparation process, the bacterial proteins were denatured and fixed in their cell membranes; consequently, protein contents were retained in the bacterial cell structures [ 54 ]. Therefore, whole-cell bacteria were not able to migrate through the porous matrix of the SDS-PAGE and became stuck in the wells [ 53 ]. Hence, to evaluate the binding capability of HNTs to FKC, S. agalactiae protein lysate was employed instead of whole-cell FKC.…”

Novel efficiently piscine orally nano-vaccine delivery system: modified halloysite nanotubes (HNTs) preventing streptococcosis disease in Tilapia (Oreochromis sp.)

“…Unfortunately, the proteins of our bivalent vaccine (formalin-killed cells -S. agalactiae) were invisible on SDS-PAGE analysis which was similar to the FKC-E. coli but some antigenic proteins could be detected by Western blot analysis [53]. It might explain that during inactivation by formalin in the vaccine preparation process, the bacterial proteins were denatured and xed in their cell membrane, consequently, protein contents were retained in the bacterial cell structure [54].…”