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Vaccine Adjuvants in Fish Vaccines Make a Difference: Comparing Three Adjuvants (Montanide ISA763A Oil, CpG/Poly I:C Combo and VHSV Glycoprotein) Alone or in Combination Formulated with an Inactivated Whole Salmonid Alphavirus Antigen.

Thim HL, Villoing S, McLoughlin M, Christie KE, Grove S, Frost P, Jørgensen JB - Vaccines (Basel) (2014)

Bottom Line: Therefore, there is a request for vaccine formulations for which protection will be maintained or improved, while the risk of side effects is reduced.Interestingly, heat-inactivated sera showed reduced nAb titres compared to their non-heated counterparts, which suggests a role of complement-mediated neutralization against SAV.The results demonstrate that a combination of pattern recognizing receptor (PRR) ligands, such as CpG/polyI:C, increases both adaptive and innate responses and represents a promising adjuvant strategy for enhancing the protection of future viral vaccines.

View Article: PubMed Central - PubMed

Affiliation: Norwegian College of Fisheries Science, UiT The Arctic University of Norway, Tromsø N-9037, Norway. hanna.l.thim@uit.no.

ABSTRACT
Most commercial vaccines offered to the aquaculture industry include inactivated antigens (Ag) formulated in oil adjuvants. Safety concerns are related to the use of oil adjuvants in multivalent vaccines for fish, since adverse side effects (e.g., adhesions) can appear. Therefore, there is a request for vaccine formulations for which protection will be maintained or improved, while the risk of side effects is reduced. Here, by using an inactivated salmonid alphavirus (SAV) as the test Ag, the combined use of two Toll-like receptor (TLR) ligand adjuvants, CpG oligonucleotides (ODNs) and poly I:C, as well as a genetic adjuvant consisting of a DNA plasmid vector expressing the viral haemorrhagic septicaemia virus (VHSV) glycoprotein (G) was explored. VHSV-G DNA vaccine was intramuscularly injected in combination with intraperitoneal injection of either SAV Ag alone or combined with the oil adjuvant, Montanide ISA763, or the CpG/polyI:C combo. Adjuvant formulations were evaluated for their ability to boost immune responses and induce protection against SAV in Atlantic salmon, following cohabitation challenge. It was observed that CpG/polyI:C-based formulations generated the highest neutralizing antibody titres (nAbs) before challenge, which endured post challenge. nAb responses for VHSV G-DNA- and oil-adjuvanted formulations were marginal compared to the CpG/poly I:C treatment. Interestingly, heat-inactivated sera showed reduced nAb titres compared to their non-heated counterparts, which suggests a role of complement-mediated neutralization against SAV. Consistently elevated levels of innate antiviral immune genes in the CpG/polyI:C injected groups suggested a role of IFN-mediated responses. Co-delivery of the VHSV-G DNA construct with either CpG/polyI:C or oil-adjuvanted SAV vaccine generated higher CD4 responses in head kidney at 48 h compared to injection of this vector or SAV Ag alone. The results demonstrate that a combination of pattern recognizing receptor (PRR) ligands, such as CpG/polyI:C, increases both adaptive and innate responses and represents a promising adjuvant strategy for enhancing the protection of future viral vaccines.

No MeSH data available.


Related in: MedlinePlus

Vaccine-induced anti-SAV neutralizing titres from not heat inactivated (A) and heat inactivated (B) sera, collected at 6 wpv, 3 wpc and 6 wpc (the colour codes for each time point are next to the y-axis). Titres representing a 50% reduction, calculated as described in the Materials and Methods, are shown above the histogram corresponding to each treatment. + or −, respectively, indicates the presence or absence of either SAV Ag, oil, CpG/polyI:C or vhsG.
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vaccines-02-00228-f003: Vaccine-induced anti-SAV neutralizing titres from not heat inactivated (A) and heat inactivated (B) sera, collected at 6 wpv, 3 wpc and 6 wpc (the colour codes for each time point are next to the y-axis). Titres representing a 50% reduction, calculated as described in the Materials and Methods, are shown above the histogram corresponding to each treatment. + or −, respectively, indicates the presence or absence of either SAV Ag, oil, CpG/polyI:C or vhsG.

Mentions: The presence of anti-SAV neutralizing responses in sera was measured at 6 wpv and at three and 6 wpc by a viral neutralization assay. It is well known that heat sensitive factors in serum may augment the neutralizing activity of Ab [45], and therefore, neutralizing activity was measured both with HI and NHI sera. For the NHI sera (Figure 3A), detectable neutralizing antibody titres (nAbTs) were present from 6 wpv for all groups, except groups treated with SAV Ag oil vhsG, vhsG alone or saline. The highest nAbTs were found in the SAV Ag CpG/polyI:C-treated group with titres of 640 before challenge that rose to 1280 and further to 2560 at three and 6 wpc, respectively. Fish treated with SAV Ag CpG/polyI:C that also received the vhsG i.m. injection showed the second highest nAbTs of 640 and 320 at 6 wpv and 3 wpc, respectively and 640 at 6 wpc. While all groups receiving a SAV Ag formulation, except the SAV Ag oil vhsG group, mounted a detectable neutralizing response before challenge, groups receiving either vhsG alone or saline had detectable nAbTs first after challenge. For vhsG alone and saline, the nAbTs are most likely induced upon exposure to the challenge virus, with titres of 80 (3 wpc) and 160 (6 wpc) for vhsG and 160 for saline at both three and 6 wpc. For HI sera, nAbTs were only present in three groups pre-challenge (Figure 3B). CpG/polyI:C-adjuvanted treatments provided the highest responses, with nAbTs ranging from 640 at 6 wpv to 1,280 at 6 wpc for SAV Ag CpG/polyI:C, and for SAV Ag CpG/polyI:C vhsG, the generation of nAbs was consistent with a titre of 160 at all sampling points. No positive sera were found among the fish injected with SAV Ag, SAV Ag oil or SAV Ag oil vhsG, while SAV Ag vhsG had detectable nAb responses both pre- and post-challenge. Fish treated with vhsG and saline, where >80% of the fish in both groups had positive SAV-specific heart lesions at 6 wpc (Figure 4B), showed detectable nAbTs at 6 wpc (80 for both treatments).


Vaccine Adjuvants in Fish Vaccines Make a Difference: Comparing Three Adjuvants (Montanide ISA763A Oil, CpG/Poly I:C Combo and VHSV Glycoprotein) Alone or in Combination Formulated with an Inactivated Whole Salmonid Alphavirus Antigen.

Thim HL, Villoing S, McLoughlin M, Christie KE, Grove S, Frost P, Jørgensen JB - Vaccines (Basel) (2014)

Vaccine-induced anti-SAV neutralizing titres from not heat inactivated (A) and heat inactivated (B) sera, collected at 6 wpv, 3 wpc and 6 wpc (the colour codes for each time point are next to the y-axis). Titres representing a 50% reduction, calculated as described in the Materials and Methods, are shown above the histogram corresponding to each treatment. + or −, respectively, indicates the presence or absence of either SAV Ag, oil, CpG/polyI:C or vhsG.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494258&req=5

vaccines-02-00228-f003: Vaccine-induced anti-SAV neutralizing titres from not heat inactivated (A) and heat inactivated (B) sera, collected at 6 wpv, 3 wpc and 6 wpc (the colour codes for each time point are next to the y-axis). Titres representing a 50% reduction, calculated as described in the Materials and Methods, are shown above the histogram corresponding to each treatment. + or −, respectively, indicates the presence or absence of either SAV Ag, oil, CpG/polyI:C or vhsG.
Mentions: The presence of anti-SAV neutralizing responses in sera was measured at 6 wpv and at three and 6 wpc by a viral neutralization assay. It is well known that heat sensitive factors in serum may augment the neutralizing activity of Ab [45], and therefore, neutralizing activity was measured both with HI and NHI sera. For the NHI sera (Figure 3A), detectable neutralizing antibody titres (nAbTs) were present from 6 wpv for all groups, except groups treated with SAV Ag oil vhsG, vhsG alone or saline. The highest nAbTs were found in the SAV Ag CpG/polyI:C-treated group with titres of 640 before challenge that rose to 1280 and further to 2560 at three and 6 wpc, respectively. Fish treated with SAV Ag CpG/polyI:C that also received the vhsG i.m. injection showed the second highest nAbTs of 640 and 320 at 6 wpv and 3 wpc, respectively and 640 at 6 wpc. While all groups receiving a SAV Ag formulation, except the SAV Ag oil vhsG group, mounted a detectable neutralizing response before challenge, groups receiving either vhsG alone or saline had detectable nAbTs first after challenge. For vhsG alone and saline, the nAbTs are most likely induced upon exposure to the challenge virus, with titres of 80 (3 wpc) and 160 (6 wpc) for vhsG and 160 for saline at both three and 6 wpc. For HI sera, nAbTs were only present in three groups pre-challenge (Figure 3B). CpG/polyI:C-adjuvanted treatments provided the highest responses, with nAbTs ranging from 640 at 6 wpv to 1,280 at 6 wpc for SAV Ag CpG/polyI:C, and for SAV Ag CpG/polyI:C vhsG, the generation of nAbs was consistent with a titre of 160 at all sampling points. No positive sera were found among the fish injected with SAV Ag, SAV Ag oil or SAV Ag oil vhsG, while SAV Ag vhsG had detectable nAb responses both pre- and post-challenge. Fish treated with vhsG and saline, where >80% of the fish in both groups had positive SAV-specific heart lesions at 6 wpc (Figure 4B), showed detectable nAbTs at 6 wpc (80 for both treatments).

Bottom Line: Therefore, there is a request for vaccine formulations for which protection will be maintained or improved, while the risk of side effects is reduced.Interestingly, heat-inactivated sera showed reduced nAb titres compared to their non-heated counterparts, which suggests a role of complement-mediated neutralization against SAV.The results demonstrate that a combination of pattern recognizing receptor (PRR) ligands, such as CpG/polyI:C, increases both adaptive and innate responses and represents a promising adjuvant strategy for enhancing the protection of future viral vaccines.

View Article: PubMed Central - PubMed

Affiliation: Norwegian College of Fisheries Science, UiT The Arctic University of Norway, Tromsø N-9037, Norway. hanna.l.thim@uit.no.

ABSTRACT
Most commercial vaccines offered to the aquaculture industry include inactivated antigens (Ag) formulated in oil adjuvants. Safety concerns are related to the use of oil adjuvants in multivalent vaccines for fish, since adverse side effects (e.g., adhesions) can appear. Therefore, there is a request for vaccine formulations for which protection will be maintained or improved, while the risk of side effects is reduced. Here, by using an inactivated salmonid alphavirus (SAV) as the test Ag, the combined use of two Toll-like receptor (TLR) ligand adjuvants, CpG oligonucleotides (ODNs) and poly I:C, as well as a genetic adjuvant consisting of a DNA plasmid vector expressing the viral haemorrhagic septicaemia virus (VHSV) glycoprotein (G) was explored. VHSV-G DNA vaccine was intramuscularly injected in combination with intraperitoneal injection of either SAV Ag alone or combined with the oil adjuvant, Montanide ISA763, or the CpG/polyI:C combo. Adjuvant formulations were evaluated for their ability to boost immune responses and induce protection against SAV in Atlantic salmon, following cohabitation challenge. It was observed that CpG/polyI:C-based formulations generated the highest neutralizing antibody titres (nAbs) before challenge, which endured post challenge. nAb responses for VHSV G-DNA- and oil-adjuvanted formulations were marginal compared to the CpG/poly I:C treatment. Interestingly, heat-inactivated sera showed reduced nAb titres compared to their non-heated counterparts, which suggests a role of complement-mediated neutralization against SAV. Consistently elevated levels of innate antiviral immune genes in the CpG/polyI:C injected groups suggested a role of IFN-mediated responses. Co-delivery of the VHSV-G DNA construct with either CpG/polyI:C or oil-adjuvanted SAV vaccine generated higher CD4 responses in head kidney at 48 h compared to injection of this vector or SAV Ag alone. The results demonstrate that a combination of pattern recognizing receptor (PRR) ligands, such as CpG/polyI:C, increases both adaptive and innate responses and represents a promising adjuvant strategy for enhancing the protection of future viral vaccines.

No MeSH data available.


Related in: MedlinePlus