Periodic Reporting for period 1 - LABVaccFish (USE OF LACTIC ACID BACTERIA AS DELIVERY VEHICLE FOR ORAL VACCINATION OF FISH)
Periodo di rendicontazione: 2016-01-04 al 2018-01-03
Since the seventies, aquaculture production has continued to grow with an average annual rate of 6.3% to reach its present 59.9 million tons of product. Despite the continuous growth of aquaculture output, outbreaks of viral diseases continue to be a significant limiting factor and the control of viruses is imperative to sustain future development of the aquaculture sector.
In this project we addressed problems related to fish vaccination, with a special focus on DNA vaccination of carp against Spring Viraemia of Carp Virus. SVCV is one of the major threats to carp production in East Europe and Asia.
In particular we evaluated the possibility to use Lactic acid bacteria (LAB) as vehicles to carry and/or deliver vaccine antigens to fish.
LAB are generally regarded as safe (GRAS); some species of LAB are very well studied beneficial microbes (probiotics) present in the intestine of humans and animals (commensals), often used as probiotics in drinks such as Actimel or Yakult.
Given their safety profile and health benefits in mammals, we decided to modify LAB, and analyse whether they could be used for oral or injection vaccination of fish.
The proof of principle that LAB can be used for vaccination of fish can provide a novel and safe approach to fish vaccination.
Since LAB could be given in the water or mixed with the feed it would provide a suitable route of mass vaccination of fish that would reduce costs and improve animal welfare by reducing stress due to handling
In this project we addressed problems related to fish vaccination, with a special focus on DNA vaccination of carp against Spring Viraemia of Carp Virus. SVCV is one of the major threats to carp production in East Europe and Asia.
In particular we evaluated the possibility to use Lactic acid bacteria (LAB) as vehicles to carry and/or deliver vaccine antigens to fish.
LAB are generally regarded as safe (GRAS); some species of LAB are very well studied beneficial microbes (probiotics) present in the intestine of humans and animals (commensals), often used as probiotics in drinks such as Actimel or Yakult.
Given their safety profile and health benefits in mammals, we decided to modify LAB, and analyse whether they could be used for oral or injection vaccination of fish.
The proof of principle that LAB can be used for vaccination of fish can provide a novel and safe approach to fish vaccination.
Since LAB could be given in the water or mixed with the feed it would provide a suitable route of mass vaccination of fish that would reduce costs and improve animal welfare by reducing stress due to handling
In this project we succeeded to modify a particular strain of LAB, L. lactis, and to optimize the conditions within which this LAB was able to deliver a vaccine antigen to the host (cells).
For the proof of principle we used a previously established vaccine antigen by our group, the spring viraemia of carp virus G protein (SVCV-G), and common carp or zebrafish as fish species.
In this project we succeeded to show that modified L.lactis can deliver the SVCV-G antigen to carp cell lines in vitro and to zebrafish larvae in vivo.
For the initial validation, bacteria were mixed in vitro with carp cells and after 3 days antigen expression in fish cells was evaluated leading to approximately 30% of the cells expressing the vaccine antigen.
For the preliminary validation in vivo, bacteria were intramuscularly injected in zebrafish larvae and antigen-expressing cells were identified already 48h after injection.
Altogether, our in vitro and in vivo results show that modified LAB can be used in fish to deliver vaccine antigens. This proof-of-principle will allow us to make the next step and test the possibility to deliver these modified bacteria to fish by bath or mixed with the feed, and to vaccinate commercially relevant species including but not limited to common carp, Tilapia, trout, salmon etc...
Details about the data will be published in an open access journal, but the manuscript is currently under preparation.
The results of the project have already been reported ot the industry through so called 'Industrial Forum' organized through a collaborative project TargetFish http://targetfish.eu/
Furthermore a short animated power point or a video will be generated following the publication of the results. These will explain in technical and layman terms the major outcomes of the project.
For the proof of principle we used a previously established vaccine antigen by our group, the spring viraemia of carp virus G protein (SVCV-G), and common carp or zebrafish as fish species.
In this project we succeeded to show that modified L.lactis can deliver the SVCV-G antigen to carp cell lines in vitro and to zebrafish larvae in vivo.
For the initial validation, bacteria were mixed in vitro with carp cells and after 3 days antigen expression in fish cells was evaluated leading to approximately 30% of the cells expressing the vaccine antigen.
For the preliminary validation in vivo, bacteria were intramuscularly injected in zebrafish larvae and antigen-expressing cells were identified already 48h after injection.
Altogether, our in vitro and in vivo results show that modified LAB can be used in fish to deliver vaccine antigens. This proof-of-principle will allow us to make the next step and test the possibility to deliver these modified bacteria to fish by bath or mixed with the feed, and to vaccinate commercially relevant species including but not limited to common carp, Tilapia, trout, salmon etc...
Details about the data will be published in an open access journal, but the manuscript is currently under preparation.
The results of the project have already been reported ot the industry through so called 'Industrial Forum' organized through a collaborative project TargetFish http://targetfish.eu/
Furthermore a short animated power point or a video will be generated following the publication of the results. These will explain in technical and layman terms the major outcomes of the project.
There is no doubt that the results of this project have provided a new toold to develop oral vaccine for fish.
What still needs to be done is to validate the modified strains in vivo in a relevant species such as common carp. The dose of bacteria will need to be optimized depending on the type of vaccine antigen and preferably under conditions where the bacteria are mixed with the feed and given orally to the fish.
This will be the ultimate validation required for the future refinement and utilization of such vaccination approach in the common practice.
Thus, further research is required for such validation but the data obtained int he current project certainly provide a very good basis for this.
What still needs to be done is to validate the modified strains in vivo in a relevant species such as common carp. The dose of bacteria will need to be optimized depending on the type of vaccine antigen and preferably under conditions where the bacteria are mixed with the feed and given orally to the fish.
This will be the ultimate validation required for the future refinement and utilization of such vaccination approach in the common practice.
Thus, further research is required for such validation but the data obtained int he current project certainly provide a very good basis for this.