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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

Analysis of the affinity of anti-VP2(aa141-155) and anti-VP1(aa208-222) against authentic EV71 and CA16 particles.(A,B) Anti-epitope antibody responses. (C,D) The anti-EV71 (C) and anti-CA16 antibody titers (D) of immune sera from mice immunized with VLPs. (E,F) Immunofluorescence assay of EV71 and CA16 infected RD cells. Immunized mouse sera were diluted 1:100 with PBS and then used to measure epitope-specific antibodies by ELISA with (A) VP1- or (B) VP2-derived epitope peptides as the coating antigen as described in the Materials and Methods. Each symbol represents one mouse.
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f4: Analysis of the affinity of anti-VP2(aa141-155) and anti-VP1(aa208-222) against authentic EV71 and CA16 particles.(A,B) Anti-epitope antibody responses. (C,D) The anti-EV71 (C) and anti-CA16 antibody titers (D) of immune sera from mice immunized with VLPs. (E,F) Immunofluorescence assay of EV71 and CA16 infected RD cells. Immunized mouse sera were diluted 1:100 with PBS and then used to measure epitope-specific antibodies by ELISA with (A) VP1- or (B) VP2-derived epitope peptides as the coating antigen as described in the Materials and Methods. Each symbol represents one mouse.

Mentions: To explore the mechanism of cross-neutralization against CA16 by the VP2 (aa141-155) containing VLPs antisera, we examined whether the immune antisera could bind both EV71 and CA16 authentic virions (Supplementary Table 1). The immunized mice sera were subsequently assayed for the anti-epitope antibodies with the VP1 or VP2 peptides as the antigen in the ELISA. Anti-epitope antibodies could be found in immunized mice after the last immunization with a dilution of 1:1000,000 (Fig. 4A,B). The antisera towards the VP1 and VP2-epitope were also assayed by ELISA where the cells expressing EV71 and CA16 virions were individually coated onto the 96-well microtiter plates. Both the chimeric VLPs HBc-E1/2 and HBc-E2 immune sera contained cross-reactivity for EV71 (OD450 = 1.78 and OD450 = 1.69) and CA16 (OD450 = 1.17 and OD450 = 1.04) with a dilution of 1:1000, whereas the HBc-E1 immune sera at the same dilution could only bind to EV71 (OD450 = 0.9) (Fig. 4C,D). Therefore, HBV core particles-surface displaying VP1 and VP2-epitope successfully retained the 3-dimensional conformation present in the corresponding virus particles. On the whole cell level, IFA was used to test the reactivity of HBc-E1 and HBc-E2 antisera with EV71 and CA16 strains-infected RD cells. As shown in Fig. 4E,F, all of the recombinant VLPs antisera showed good reactivity with the EV71 virus but not in non-infected cells. In contrast, HBc-E2 antisera also led to significant binding activity in CA16-infected cells, whereas HBc-E1 did not. Therefore, these data demonstrate that anti-VP2 (aa141-155), but not anti-VP1(aa208-222), could cross-react with normal EV71 and CA16 virions.


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)

Analysis of the affinity of anti-VP2(aa141-155) and anti-VP1(aa208-222) against authentic EV71 and CA16 particles.(A,B) Anti-epitope antibody responses. (C,D) The anti-EV71 (C) and anti-CA16 antibody titers (D) of immune sera from mice immunized with VLPs. (E,F) Immunofluorescence assay of EV71 and CA16 infected RD cells. Immunized mouse sera were diluted 1:100 with PBS and then used to measure epitope-specific antibodies by ELISA with (A) VP1- or (B) VP2-derived epitope peptides as the coating antigen as described in the Materials and Methods. Each symbol represents one mouse.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: Analysis of the affinity of anti-VP2(aa141-155) and anti-VP1(aa208-222) against authentic EV71 and CA16 particles.(A,B) Anti-epitope antibody responses. (C,D) The anti-EV71 (C) and anti-CA16 antibody titers (D) of immune sera from mice immunized with VLPs. (E,F) Immunofluorescence assay of EV71 and CA16 infected RD cells. Immunized mouse sera were diluted 1:100 with PBS and then used to measure epitope-specific antibodies by ELISA with (A) VP1- or (B) VP2-derived epitope peptides as the coating antigen as described in the Materials and Methods. Each symbol represents one mouse.
Mentions: To explore the mechanism of cross-neutralization against CA16 by the VP2 (aa141-155) containing VLPs antisera, we examined whether the immune antisera could bind both EV71 and CA16 authentic virions (Supplementary Table 1). The immunized mice sera were subsequently assayed for the anti-epitope antibodies with the VP1 or VP2 peptides as the antigen in the ELISA. Anti-epitope antibodies could be found in immunized mice after the last immunization with a dilution of 1:1000,000 (Fig. 4A,B). The antisera towards the VP1 and VP2-epitope were also assayed by ELISA where the cells expressing EV71 and CA16 virions were individually coated onto the 96-well microtiter plates. Both the chimeric VLPs HBc-E1/2 and HBc-E2 immune sera contained cross-reactivity for EV71 (OD450 = 1.78 and OD450 = 1.69) and CA16 (OD450 = 1.17 and OD450 = 1.04) with a dilution of 1:1000, whereas the HBc-E1 immune sera at the same dilution could only bind to EV71 (OD450 = 0.9) (Fig. 4C,D). Therefore, HBV core particles-surface displaying VP1 and VP2-epitope successfully retained the 3-dimensional conformation present in the corresponding virus particles. On the whole cell level, IFA was used to test the reactivity of HBc-E1 and HBc-E2 antisera with EV71 and CA16 strains-infected RD cells. As shown in Fig. 4E,F, all of the recombinant VLPs antisera showed good reactivity with the EV71 virus but not in non-infected cells. In contrast, HBc-E2 antisera also led to significant binding activity in CA16-infected cells, whereas HBc-E1 did not. Therefore, these data demonstrate that anti-VP2 (aa141-155), but not anti-VP1(aa208-222), could cross-react with normal EV71 and CA16 virions.

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