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A Broadly Cross-protective Vaccine Presenting the Neighboring Epitopes within the VP1 GH Loop and VP2 EF Loop of Enterovirus 71.

Xu L, He D, Yang L, Li Z, Ye X, Yu H, zhao H, Li S, Yuan L, Qian H, Que Y, Shih JW, Zhu H, Li Y, Cheng T, Xia N - Sci Rep (2015)

Bottom Line: We demonstrate that anti-VP2 (aa141-155) sera bound authentic CA16 viral particles, whereas anti-VP1 (aa208-222) sera could not.Moreover, the anti-VP2 (aa141-155) antibodies inhibited the binding of human serum to virions, which demonstrated that the VP2 epitope is immunodominant between EV71 and CA16.These results illustrated that the chimeric VLP HBc-E1/2 is a promising candidate for a broad-spectrum HFMD vaccine, and also reveals mechanisms of protection by the neighboring linear epitopes of the VP1 GH and VP2 EF loops.

View Article: PubMed Central - PubMed

Affiliation: National Institute of Diagnostics and Vaccine Development in infectious diseases, School of Public Health, Xiamen University, Xiamen 361102, PR China.

ABSTRACT
Human enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the major etiological agents of hand, foot and mouth disease (HFMD) and are often associated with neurological complications. Currently, several vaccine types are being developed for EV71 and CA16. In this study, we constructed a bivalent chimeric virus-like particle (VLP) presenting the VP1 (aa208-222) and VP2 (aa141-155) epitopes of EV71 using hepatitis B virus core protein (HBc) as a carrier, designated HBc-E1/2. Immunization with the chimeric VLPs HBc-E1/2 induced higher IgG titers and neutralization titers against EV71 and CA16 in vitro than immunization with only one epitope incorporated into HBc. Importantly, passive immunization with the recombinant HBc-E2 particles protected neonatal mice against lethal EV71 and CA16 infections. We demonstrate that anti-VP2 (aa141-155) sera bound authentic CA16 viral particles, whereas anti-VP1 (aa208-222) sera could not. Moreover, the anti-VP2 (aa141-155) antibodies inhibited the binding of human serum to virions, which demonstrated that the VP2 epitope is immunodominant between EV71 and CA16. These results illustrated that the chimeric VLP HBc-E1/2 is a promising candidate for a broad-spectrum HFMD vaccine, and also reveals mechanisms of protection by the neighboring linear epitopes of the VP1 GH and VP2 EF loops.

No MeSH data available.


Related in: MedlinePlus

Kinetics of anti-epitope antibody responses.Groups of five mice were immunized with 0.625, 1.25, 10 and 100 μg/dose i.p. at weeks 0, 2 and 4 with HBc-E1/2, HBc-E1, HBc-E2 or HBc(aa1-149) as described in the Materials and Methods. Sera were collected at 0, 2, 4, 6, 8, 10 and 12 for the serological tests and analyzed by ELISA to measure the epitope-specific antibody response, the VP1(aa208-222)-specific antibody response (A,C,E,G) and the VP2(aa141-155)-specific antibody response (B,D,F,H). All serum samples were prepared using 10-fold dilution series, and the first dilution was 100-fold. Each point represents the mean reciprocal log10 endpoint titers and standard error.
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f2: Kinetics of anti-epitope antibody responses.Groups of five mice were immunized with 0.625, 1.25, 10 and 100 μg/dose i.p. at weeks 0, 2 and 4 with HBc-E1/2, HBc-E1, HBc-E2 or HBc(aa1-149) as described in the Materials and Methods. Sera were collected at 0, 2, 4, 6, 8, 10 and 12 for the serological tests and analyzed by ELISA to measure the epitope-specific antibody response, the VP1(aa208-222)-specific antibody response (A,C,E,G) and the VP2(aa141-155)-specific antibody response (B,D,F,H). All serum samples were prepared using 10-fold dilution series, and the first dilution was 100-fold. Each point represents the mean reciprocal log10 endpoint titers and standard error.

Mentions: To ascertain and compare the immunogenicity and protective properties of the VLP, both BALB/c mice and Wistar rat were used in this study. Groups of 5 female BALB/c mice were immunized with 0.625, 1.25, 10 and 100 μg/dose of one of the following samples: recombinant VLPs HBc-E1, HBc-E2, and the bivalent chimeric VLPs HBc-E1/2. Another group of mice were injected with HBc (aa1-149) as the control. The VLPs in saline were i.p. injected, with aluminum adjuvant. Booster doses were given on days 14 and 28 post-immunization. The immunized mice sera were subsequently assayed for the anti-epitope antibodies with the purified rVP1 or rVP2 protein as the antigen in the ELISA. Because we used rVP1 or rVP2 as the coated protein of the ELISA, the anti-VP1 or VP2 titer actually represented the epitope specific antibodies in the sera of recombinant VLPs immunized mice. The groups immunized with 1.25, 10 and 100 μg/dose, anti-epitope antibodies could be found in immunized mice after the primary immunization, and these antibody levels increased substantially after the booster doses were administered (Fig. 2). Figure 2A-D shows that the groups receiving 10 and 100 μg/dose chimeric VLPs HBc-E1/2 showed 2.8-fold-higher anti-VP1 antibody titers (titers ranging from 1:280,000 to 1:460,000) and 2.8-fold-higher anti-VP2 antibody titers (titers ranging from 1:280,000 to 1:8,200,000) compared to group of 0.625 and 1.25 μg/dose (Fig. 2E–H). We also tested the immunization capacity of the VLPs. The HBc-E1 and HBc-E2 antisera did not show significant immunization activity in the group receiving 0.625 μg/dose, whereas the anti-epitope titers of the HBc-E1/2 antisera increased after the second dose (anti-VP1 titers of 1:64,000 and anti-VP2 titers of 1:100,000) (Fig. 2G,H). These results demonstrated that the bivalent HBc-E1/2 VLPs were more immunogenic than HBc-E1 and HBc-E2 with a single epitope insertion, while the high dose of recombinant VLPs induced a higher antibody response than the low dose.


A Broadly Cross-protective Vaccine Presenting the Neighboring Epitopes within the VP1 GH Loop and VP2 EF Loop of Enterovirus 71.

Xu L, He D, Yang L, Li Z, Ye X, Yu H, zhao H, Li S, Yuan L, Qian H, Que Y, Shih JW, Zhu H, Li Y, Cheng T, Xia N - Sci Rep (2015)

Kinetics of anti-epitope antibody responses.Groups of five mice were immunized with 0.625, 1.25, 10 and 100 μg/dose i.p. at weeks 0, 2 and 4 with HBc-E1/2, HBc-E1, HBc-E2 or HBc(aa1-149) as described in the Materials and Methods. Sera were collected at 0, 2, 4, 6, 8, 10 and 12 for the serological tests and analyzed by ELISA to measure the epitope-specific antibody response, the VP1(aa208-222)-specific antibody response (A,C,E,G) and the VP2(aa141-155)-specific antibody response (B,D,F,H). All serum samples were prepared using 10-fold dilution series, and the first dilution was 100-fold. Each point represents the mean reciprocal log10 endpoint titers and standard error.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525384&req=5

f2: Kinetics of anti-epitope antibody responses.Groups of five mice were immunized with 0.625, 1.25, 10 and 100 μg/dose i.p. at weeks 0, 2 and 4 with HBc-E1/2, HBc-E1, HBc-E2 or HBc(aa1-149) as described in the Materials and Methods. Sera were collected at 0, 2, 4, 6, 8, 10 and 12 for the serological tests and analyzed by ELISA to measure the epitope-specific antibody response, the VP1(aa208-222)-specific antibody response (A,C,E,G) and the VP2(aa141-155)-specific antibody response (B,D,F,H). All serum samples were prepared using 10-fold dilution series, and the first dilution was 100-fold. Each point represents the mean reciprocal log10 endpoint titers and standard error.
Mentions: To ascertain and compare the immunogenicity and protective properties of the VLP, both BALB/c mice and Wistar rat were used in this study. Groups of 5 female BALB/c mice were immunized with 0.625, 1.25, 10 and 100 μg/dose of one of the following samples: recombinant VLPs HBc-E1, HBc-E2, and the bivalent chimeric VLPs HBc-E1/2. Another group of mice were injected with HBc (aa1-149) as the control. The VLPs in saline were i.p. injected, with aluminum adjuvant. Booster doses were given on days 14 and 28 post-immunization. The immunized mice sera were subsequently assayed for the anti-epitope antibodies with the purified rVP1 or rVP2 protein as the antigen in the ELISA. Because we used rVP1 or rVP2 as the coated protein of the ELISA, the anti-VP1 or VP2 titer actually represented the epitope specific antibodies in the sera of recombinant VLPs immunized mice. The groups immunized with 1.25, 10 and 100 μg/dose, anti-epitope antibodies could be found in immunized mice after the primary immunization, and these antibody levels increased substantially after the booster doses were administered (Fig. 2). Figure 2A-D shows that the groups receiving 10 and 100 μg/dose chimeric VLPs HBc-E1/2 showed 2.8-fold-higher anti-VP1 antibody titers (titers ranging from 1:280,000 to 1:460,000) and 2.8-fold-higher anti-VP2 antibody titers (titers ranging from 1:280,000 to 1:8,200,000) compared to group of 0.625 and 1.25 μg/dose (Fig. 2E–H). We also tested the immunization capacity of the VLPs. The HBc-E1 and HBc-E2 antisera did not show significant immunization activity in the group receiving 0.625 μg/dose, whereas the anti-epitope titers of the HBc-E1/2 antisera increased after the second dose (anti-VP1 titers of 1:64,000 and anti-VP2 titers of 1:100,000) (Fig. 2G,H). These results demonstrated that the bivalent HBc-E1/2 VLPs were more immunogenic than HBc-E1 and HBc-E2 with a single epitope insertion, while the high dose of recombinant VLPs induced a higher antibody response than the low dose.

Bottom Line: We demonstrate that anti-VP2 (aa141-155) sera bound authentic CA16 viral particles, whereas anti-VP1 (aa208-222) sera could not.Moreover, the anti-VP2 (aa141-155) antibodies inhibited the binding of human serum to virions, which demonstrated that the VP2 epitope is immunodominant between EV71 and CA16.These results illustrated that the chimeric VLP HBc-E1/2 is a promising candidate for a broad-spectrum HFMD vaccine, and also reveals mechanisms of protection by the neighboring linear epitopes of the VP1 GH and VP2 EF loops.

View Article: PubMed Central - PubMed

Affiliation: National Institute of Diagnostics and Vaccine Development in infectious diseases, School of Public Health, Xiamen University, Xiamen 361102, PR China.

ABSTRACT
Human enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the major etiological agents of hand, foot and mouth disease (HFMD) and are often associated with neurological complications. Currently, several vaccine types are being developed for EV71 and CA16. In this study, we constructed a bivalent chimeric virus-like particle (VLP) presenting the VP1 (aa208-222) and VP2 (aa141-155) epitopes of EV71 using hepatitis B virus core protein (HBc) as a carrier, designated HBc-E1/2. Immunization with the chimeric VLPs HBc-E1/2 induced higher IgG titers and neutralization titers against EV71 and CA16 in vitro than immunization with only one epitope incorporated into HBc. Importantly, passive immunization with the recombinant HBc-E2 particles protected neonatal mice against lethal EV71 and CA16 infections. We demonstrate that anti-VP2 (aa141-155) sera bound authentic CA16 viral particles, whereas anti-VP1 (aa208-222) sera could not. Moreover, the anti-VP2 (aa141-155) antibodies inhibited the binding of human serum to virions, which demonstrated that the VP2 epitope is immunodominant between EV71 and CA16. These results illustrated that the chimeric VLP HBc-E1/2 is a promising candidate for a broad-spectrum HFMD vaccine, and also reveals mechanisms of protection by the neighboring linear epitopes of the VP1 GH and VP2 EF loops.

No MeSH data available.


Related in: MedlinePlus