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Single-dose attenuated Vesiculovax vaccines protect primates against Ebola Makona virus.

Mire CE, Matassov D, Geisbert JB, Latham TE, Agans KN, Xu R, Ota-Setlik A, Egan MA, Fenton KA, Clarke DK, Eldridge JH, Geisbert TW - Nature (2015)

Bottom Line: During 2014 an unprecedented ZEBOV outbreak occurred in West Africa and is still ongoing, resulting in over 10,000 deaths, and causing global concern of uncontrolled disease.To address safety concerns associated with this vector, we developed two candidate, further-attenuated rVSV/ZEBOV vaccines.Both attenuated vaccines produced an approximately tenfold lower vaccine-associated viraemia compared to the first-generation vaccine and both provided complete, single-dose protection of macaques from lethal challenge with the Makona outbreak strain of ZEBOV.

View Article: PubMed Central - PubMed

Affiliation: 1] Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas 77550, USA [2] Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77550, USA.

ABSTRACT
The family Filoviridae contains three genera, Ebolavirus (EBOV), Marburg virus, and Cuevavirus. Some members of the EBOV genus, including Zaire ebolavirus (ZEBOV), can cause lethal haemorrhagic fever in humans. During 2014 an unprecedented ZEBOV outbreak occurred in West Africa and is still ongoing, resulting in over 10,000 deaths, and causing global concern of uncontrolled disease. To meet this challenge a rapid-acting vaccine is needed. Many vaccine approaches have shown promise in being able to protect nonhuman primates against ZEBOV. In response to the current ZEBOV outbreak several of these vaccines have been fast tracked for human use. However, it is not known whether any of these vaccines can provide protection against the new outbreak Makona strain of ZEBOV. One of these approaches is a first-generation recombinant vesicular stomatitis virus (rVSV)-based vaccine expressing the ZEBOV glycoprotein (GP) (rVSV/ZEBOV). To address safety concerns associated with this vector, we developed two candidate, further-attenuated rVSV/ZEBOV vaccines. Both attenuated vaccines produced an approximately tenfold lower vaccine-associated viraemia compared to the first-generation vaccine and both provided complete, single-dose protection of macaques from lethal challenge with the Makona outbreak strain of ZEBOV.

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rVSV/ZEBOV vector design, growth kinetics and vaccine study strategya. Genome organization comparing ZEBOV GP (Mayinga strain) expressing rVSV vectors as described in methods. The rVSV/ZEBOVΔG (ΔG) vector had the natural VSV G gene replaced with the ZEBOV GP at position 4 within the genome. rVSVN1CT1GP3 (N1) vector retained the position of VSV N in position 1 (red box), insertion of ZEBOV GP at position 3 and a truncated form of VSV G containing the CT1 truncation was inserted at position 6. The rVSVN4CT1GP1 (N4) vector had the insertion of ZEBOV GP in position 1, attenuating N gene translocation (N4) (black box) and truncated G protein cytoplasmic tail (CT1). Numbers above vector constructs designate genome positions. Virus leader (Le), trailer (Tr), and intergenic regions are shown in black. Shaded regions represent deleted amino acid regions. b. Single-cycle growth kinetics comparing the ΔG, N1, and N4 vectors depicted in (a). Data shown are mean ± SD from two biological replicates titrated by plaque assay in triplicate. Titer differences between ΔG and N1 vectors were statistically significant at 4 (p = 0.0001, 12 (p = 0.0055), and 24 hours post infection (p = 0.0001). Likewise, ΔG and N4 vector titers were significantly different at 4 (p = 0.0001), 12 (p = 0.0005), 24 (p = 0.0001), and 48 hours post infection (p = 0.0068). Unpaired t-test, p = 0.05. c. Crystal violet stained Vero cell monolayers showing plaques generated by the ΔG, N1, and N4 vectors at 48 hours post infection. d. Flow chart showing the days of vaccination (triangles), days of sampling (arrows), day of challenge (*). Blue triangle, unvaccinated cohort; orange triangle, N1 vaccinated cohort; black triangle, N4 vaccinated cohort.
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Figure 1: rVSV/ZEBOV vector design, growth kinetics and vaccine study strategya. Genome organization comparing ZEBOV GP (Mayinga strain) expressing rVSV vectors as described in methods. The rVSV/ZEBOVΔG (ΔG) vector had the natural VSV G gene replaced with the ZEBOV GP at position 4 within the genome. rVSVN1CT1GP3 (N1) vector retained the position of VSV N in position 1 (red box), insertion of ZEBOV GP at position 3 and a truncated form of VSV G containing the CT1 truncation was inserted at position 6. The rVSVN4CT1GP1 (N4) vector had the insertion of ZEBOV GP in position 1, attenuating N gene translocation (N4) (black box) and truncated G protein cytoplasmic tail (CT1). Numbers above vector constructs designate genome positions. Virus leader (Le), trailer (Tr), and intergenic regions are shown in black. Shaded regions represent deleted amino acid regions. b. Single-cycle growth kinetics comparing the ΔG, N1, and N4 vectors depicted in (a). Data shown are mean ± SD from two biological replicates titrated by plaque assay in triplicate. Titer differences between ΔG and N1 vectors were statistically significant at 4 (p = 0.0001, 12 (p = 0.0055), and 24 hours post infection (p = 0.0001). Likewise, ΔG and N4 vector titers were significantly different at 4 (p = 0.0001), 12 (p = 0.0005), 24 (p = 0.0001), and 48 hours post infection (p = 0.0068). Unpaired t-test, p = 0.05. c. Crystal violet stained Vero cell monolayers showing plaques generated by the ΔG, N1, and N4 vectors at 48 hours post infection. d. Flow chart showing the days of vaccination (triangles), days of sampling (arrows), day of challenge (*). Blue triangle, unvaccinated cohort; orange triangle, N1 vaccinated cohort; black triangle, N4 vaccinated cohort.

Mentions: To address this possible safety concern we have developed and tested two further attenuated rVSV/ZEBOV vaccine candidates for efficacy. One of these vaccines is based on an rVSV vector that has advanced through clinical evaluation. It was attenuated by translocating the VSV nucleoprotein (N) gene from position 1 to position 4 in the genome (N4) and truncating the cytoplasmic tail (CT) of the VSV G protein from 29 amino acids (aa) to 1 aa (CT1)11. This rVSVN4CT1 vector was modified to maximally express HIV-1 gag from position 1 in the genome (rVSVN4CT1gag1) by positioning the gag gene immediately adjacent to the single strong 3’ VSV transcription promoter. The rVSVN4CT1gag1 vector has demonstrated safety in mouse and NHP neurovirulence studies11,12, and replication is restricted to the IM inoculation site and draining lymph node following vaccination of mice13. The rVSVN4CT1gag1 vector has demonstrated safety and immunogenicity in two Phase I clinical trials (HVTN 090 and HVTN 087: http://clinicaltrials.gov/) and no post vaccination viremia was detected in urine, saliva, and blood of vaccine recipients. The rVSVN4CT1GP1 vector described here (Fig. 1a, N4) is analogous in design to that rVSVN4CT1gag1 vaccine and expresses ZEBOV GP from genome position 1. The other attenuated rVSV/ZEBOV vaccine described here (rVSVN1CT1GP3) expressing a truncated form of VSV G was designed to be of intermediate attenuation between rVSVN4CT1GP1 and the first generation rVSV/ZEBOVΔG vaccine (Fig. 1a, N1). Both attenuated rVSV/ZEBOV vectors express GP from the ZEBOV Mayinga strain, as do most other candidate ZEBOV vaccines currently under evaluation. Sequence homology between GPs from the new West African Makona strains analyzed to date and the 1976 Mayinga strain is approximately 97%. While this difference is not likely to affect the protective efficacy of the current ZEBOV vaccines against the heterologous West African strains, it is possible that small changes in sequence could lead to reduced efficacy of a vaccine14. It is well established that small variations in sequence and even single amino acid changes in sequence for other viruses including influenza, respiratory syncytial virus, polio, equine infectious anemia virus, and SIV can reduce vaccine efficacy. Here, we assessed the ability of our newly developed next generation rVSV-based vaccines expressing ZEBOV Mayinga GP to protect against heterologous challenge with the new outbreak Makona strain of ZEBOV in cynomolgus monkeys.


Single-dose attenuated Vesiculovax vaccines protect primates against Ebola Makona virus.

Mire CE, Matassov D, Geisbert JB, Latham TE, Agans KN, Xu R, Ota-Setlik A, Egan MA, Fenton KA, Clarke DK, Eldridge JH, Geisbert TW - Nature (2015)

rVSV/ZEBOV vector design, growth kinetics and vaccine study strategya. Genome organization comparing ZEBOV GP (Mayinga strain) expressing rVSV vectors as described in methods. The rVSV/ZEBOVΔG (ΔG) vector had the natural VSV G gene replaced with the ZEBOV GP at position 4 within the genome. rVSVN1CT1GP3 (N1) vector retained the position of VSV N in position 1 (red box), insertion of ZEBOV GP at position 3 and a truncated form of VSV G containing the CT1 truncation was inserted at position 6. The rVSVN4CT1GP1 (N4) vector had the insertion of ZEBOV GP in position 1, attenuating N gene translocation (N4) (black box) and truncated G protein cytoplasmic tail (CT1). Numbers above vector constructs designate genome positions. Virus leader (Le), trailer (Tr), and intergenic regions are shown in black. Shaded regions represent deleted amino acid regions. b. Single-cycle growth kinetics comparing the ΔG, N1, and N4 vectors depicted in (a). Data shown are mean ± SD from two biological replicates titrated by plaque assay in triplicate. Titer differences between ΔG and N1 vectors were statistically significant at 4 (p = 0.0001, 12 (p = 0.0055), and 24 hours post infection (p = 0.0001). Likewise, ΔG and N4 vector titers were significantly different at 4 (p = 0.0001), 12 (p = 0.0005), 24 (p = 0.0001), and 48 hours post infection (p = 0.0068). Unpaired t-test, p = 0.05. c. Crystal violet stained Vero cell monolayers showing plaques generated by the ΔG, N1, and N4 vectors at 48 hours post infection. d. Flow chart showing the days of vaccination (triangles), days of sampling (arrows), day of challenge (*). Blue triangle, unvaccinated cohort; orange triangle, N1 vaccinated cohort; black triangle, N4 vaccinated cohort.
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Related In: Results  -  Collection

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Figure 1: rVSV/ZEBOV vector design, growth kinetics and vaccine study strategya. Genome organization comparing ZEBOV GP (Mayinga strain) expressing rVSV vectors as described in methods. The rVSV/ZEBOVΔG (ΔG) vector had the natural VSV G gene replaced with the ZEBOV GP at position 4 within the genome. rVSVN1CT1GP3 (N1) vector retained the position of VSV N in position 1 (red box), insertion of ZEBOV GP at position 3 and a truncated form of VSV G containing the CT1 truncation was inserted at position 6. The rVSVN4CT1GP1 (N4) vector had the insertion of ZEBOV GP in position 1, attenuating N gene translocation (N4) (black box) and truncated G protein cytoplasmic tail (CT1). Numbers above vector constructs designate genome positions. Virus leader (Le), trailer (Tr), and intergenic regions are shown in black. Shaded regions represent deleted amino acid regions. b. Single-cycle growth kinetics comparing the ΔG, N1, and N4 vectors depicted in (a). Data shown are mean ± SD from two biological replicates titrated by plaque assay in triplicate. Titer differences between ΔG and N1 vectors were statistically significant at 4 (p = 0.0001, 12 (p = 0.0055), and 24 hours post infection (p = 0.0001). Likewise, ΔG and N4 vector titers were significantly different at 4 (p = 0.0001), 12 (p = 0.0005), 24 (p = 0.0001), and 48 hours post infection (p = 0.0068). Unpaired t-test, p = 0.05. c. Crystal violet stained Vero cell monolayers showing plaques generated by the ΔG, N1, and N4 vectors at 48 hours post infection. d. Flow chart showing the days of vaccination (triangles), days of sampling (arrows), day of challenge (*). Blue triangle, unvaccinated cohort; orange triangle, N1 vaccinated cohort; black triangle, N4 vaccinated cohort.
Mentions: To address this possible safety concern we have developed and tested two further attenuated rVSV/ZEBOV vaccine candidates for efficacy. One of these vaccines is based on an rVSV vector that has advanced through clinical evaluation. It was attenuated by translocating the VSV nucleoprotein (N) gene from position 1 to position 4 in the genome (N4) and truncating the cytoplasmic tail (CT) of the VSV G protein from 29 amino acids (aa) to 1 aa (CT1)11. This rVSVN4CT1 vector was modified to maximally express HIV-1 gag from position 1 in the genome (rVSVN4CT1gag1) by positioning the gag gene immediately adjacent to the single strong 3’ VSV transcription promoter. The rVSVN4CT1gag1 vector has demonstrated safety in mouse and NHP neurovirulence studies11,12, and replication is restricted to the IM inoculation site and draining lymph node following vaccination of mice13. The rVSVN4CT1gag1 vector has demonstrated safety and immunogenicity in two Phase I clinical trials (HVTN 090 and HVTN 087: http://clinicaltrials.gov/) and no post vaccination viremia was detected in urine, saliva, and blood of vaccine recipients. The rVSVN4CT1GP1 vector described here (Fig. 1a, N4) is analogous in design to that rVSVN4CT1gag1 vaccine and expresses ZEBOV GP from genome position 1. The other attenuated rVSV/ZEBOV vaccine described here (rVSVN1CT1GP3) expressing a truncated form of VSV G was designed to be of intermediate attenuation between rVSVN4CT1GP1 and the first generation rVSV/ZEBOVΔG vaccine (Fig. 1a, N1). Both attenuated rVSV/ZEBOV vectors express GP from the ZEBOV Mayinga strain, as do most other candidate ZEBOV vaccines currently under evaluation. Sequence homology between GPs from the new West African Makona strains analyzed to date and the 1976 Mayinga strain is approximately 97%. While this difference is not likely to affect the protective efficacy of the current ZEBOV vaccines against the heterologous West African strains, it is possible that small changes in sequence could lead to reduced efficacy of a vaccine14. It is well established that small variations in sequence and even single amino acid changes in sequence for other viruses including influenza, respiratory syncytial virus, polio, equine infectious anemia virus, and SIV can reduce vaccine efficacy. Here, we assessed the ability of our newly developed next generation rVSV-based vaccines expressing ZEBOV Mayinga GP to protect against heterologous challenge with the new outbreak Makona strain of ZEBOV in cynomolgus monkeys.

Bottom Line: During 2014 an unprecedented ZEBOV outbreak occurred in West Africa and is still ongoing, resulting in over 10,000 deaths, and causing global concern of uncontrolled disease.To address safety concerns associated with this vector, we developed two candidate, further-attenuated rVSV/ZEBOV vaccines.Both attenuated vaccines produced an approximately tenfold lower vaccine-associated viraemia compared to the first-generation vaccine and both provided complete, single-dose protection of macaques from lethal challenge with the Makona outbreak strain of ZEBOV.

View Article: PubMed Central - PubMed

Affiliation: 1] Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas 77550, USA [2] Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77550, USA.

ABSTRACT
The family Filoviridae contains three genera, Ebolavirus (EBOV), Marburg virus, and Cuevavirus. Some members of the EBOV genus, including Zaire ebolavirus (ZEBOV), can cause lethal haemorrhagic fever in humans. During 2014 an unprecedented ZEBOV outbreak occurred in West Africa and is still ongoing, resulting in over 10,000 deaths, and causing global concern of uncontrolled disease. To meet this challenge a rapid-acting vaccine is needed. Many vaccine approaches have shown promise in being able to protect nonhuman primates against ZEBOV. In response to the current ZEBOV outbreak several of these vaccines have been fast tracked for human use. However, it is not known whether any of these vaccines can provide protection against the new outbreak Makona strain of ZEBOV. One of these approaches is a first-generation recombinant vesicular stomatitis virus (rVSV)-based vaccine expressing the ZEBOV glycoprotein (GP) (rVSV/ZEBOV). To address safety concerns associated with this vector, we developed two candidate, further-attenuated rVSV/ZEBOV vaccines. Both attenuated vaccines produced an approximately tenfold lower vaccine-associated viraemia compared to the first-generation vaccine and both provided complete, single-dose protection of macaques from lethal challenge with the Makona outbreak strain of ZEBOV.

Show MeSH
Related in: MedlinePlus