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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

Sequence alignment of the cross-neutralizing epitope of VP1(aa208-222) and VP2(aa141-155) from NCBI database.(A) The quality of conservation of epitope sequence alignment and Epitopes sequence logo. The sequence logo was created using Weblogo (http://weblogo.berkeley.edu/logo.cgi). Bits represent the relative frequency of amino acids. (B) Comparison of the cross-neutralizing epitope of VP1 (aa208-222) and VP2 (aa141-155) between EV71 and CA16 based on molecular modeling of the mature EV71 virion structure (PDB: 3VBS). The cross-neutralizing epitope of VP2 is shown in yellows (EV71) and salmon (CA16) on the canyon region, together with the GH loop of VP1, which is in cyan (EV71) and magentas (CA16). The amino acid sequence of the EV71-VP1 GH loop differed from that of CA16 at position K215L, E217A and K218N (A,B). Stereo pictures showing the VP1 and VP2-epitope between EV71 and CA16 (C). All models were prepared using PyMOL (DeLano Scientific).
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f6: Sequence alignment of the cross-neutralizing epitope of VP1(aa208-222) and VP2(aa141-155) from NCBI database.(A) The quality of conservation of epitope sequence alignment and Epitopes sequence logo. The sequence logo was created using Weblogo (http://weblogo.berkeley.edu/logo.cgi). Bits represent the relative frequency of amino acids. (B) Comparison of the cross-neutralizing epitope of VP1 (aa208-222) and VP2 (aa141-155) between EV71 and CA16 based on molecular modeling of the mature EV71 virion structure (PDB: 3VBS). The cross-neutralizing epitope of VP2 is shown in yellows (EV71) and salmon (CA16) on the canyon region, together with the GH loop of VP1, which is in cyan (EV71) and magentas (CA16). The amino acid sequence of the EV71-VP1 GH loop differed from that of CA16 at position K215L, E217A and K218N (A,B). Stereo pictures showing the VP1 and VP2-epitope between EV71 and CA16 (C). All models were prepared using PyMOL (DeLano Scientific).

Mentions: To investigate the mechanism underlying the cross-reactivity of the anti-HBc-E1/2 or anti-HBc-E2, but not the anti-HBc-E1, with CA16 strains, we next aligned the critical amino acid residues to further characterize the neutralization epitopes using the ClustalW2 program. The two neutralizing epitopes are shown in Weblogo format (Fig. 6A). According to the BLAST results, the epitope KQEK (highlighted in grey) was fully conserved among the strains of different EV71 sub-genogroups. In contrast, the epitope was found substantially differ in CA16 consistent with its restricted cross-reactivity. The results of our previous alanine (Ala) substitution studies suggested that the critical amino acid residues within the VP2 epitope are Thr (T141), Glu (E142), Ser (S144) and His (H145). The amino acid sequence alignment of the VP2 epitope between EV71 and CA16 showed that it is relatively well conserved with only one variant amino acid sites (residues T141N) among the critical residues. In addition, the VP2 epitope of CA16-190 (the virus used in the passive protection study) is conserved among different genotypes. This finding may also explain why the HBc-E1/2 and HBc-E2 vaccine can cross-react with normal 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)

Sequence alignment of the cross-neutralizing epitope of VP1(aa208-222) and VP2(aa141-155) from NCBI database.(A) The quality of conservation of epitope sequence alignment and Epitopes sequence logo. The sequence logo was created using Weblogo (http://weblogo.berkeley.edu/logo.cgi). Bits represent the relative frequency of amino acids. (B) Comparison of the cross-neutralizing epitope of VP1 (aa208-222) and VP2 (aa141-155) between EV71 and CA16 based on molecular modeling of the mature EV71 virion structure (PDB: 3VBS). The cross-neutralizing epitope of VP2 is shown in yellows (EV71) and salmon (CA16) on the canyon region, together with the GH loop of VP1, which is in cyan (EV71) and magentas (CA16). The amino acid sequence of the EV71-VP1 GH loop differed from that of CA16 at position K215L, E217A and K218N (A,B). Stereo pictures showing the VP1 and VP2-epitope between EV71 and CA16 (C). All models were prepared using PyMOL (DeLano Scientific).
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Related In: Results  -  Collection

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f6: Sequence alignment of the cross-neutralizing epitope of VP1(aa208-222) and VP2(aa141-155) from NCBI database.(A) The quality of conservation of epitope sequence alignment and Epitopes sequence logo. The sequence logo was created using Weblogo (http://weblogo.berkeley.edu/logo.cgi). Bits represent the relative frequency of amino acids. (B) Comparison of the cross-neutralizing epitope of VP1 (aa208-222) and VP2 (aa141-155) between EV71 and CA16 based on molecular modeling of the mature EV71 virion structure (PDB: 3VBS). The cross-neutralizing epitope of VP2 is shown in yellows (EV71) and salmon (CA16) on the canyon region, together with the GH loop of VP1, which is in cyan (EV71) and magentas (CA16). The amino acid sequence of the EV71-VP1 GH loop differed from that of CA16 at position K215L, E217A and K218N (A,B). Stereo pictures showing the VP1 and VP2-epitope between EV71 and CA16 (C). All models were prepared using PyMOL (DeLano Scientific).
Mentions: To investigate the mechanism underlying the cross-reactivity of the anti-HBc-E1/2 or anti-HBc-E2, but not the anti-HBc-E1, with CA16 strains, we next aligned the critical amino acid residues to further characterize the neutralization epitopes using the ClustalW2 program. The two neutralizing epitopes are shown in Weblogo format (Fig. 6A). According to the BLAST results, the epitope KQEK (highlighted in grey) was fully conserved among the strains of different EV71 sub-genogroups. In contrast, the epitope was found substantially differ in CA16 consistent with its restricted cross-reactivity. The results of our previous alanine (Ala) substitution studies suggested that the critical amino acid residues within the VP2 epitope are Thr (T141), Glu (E142), Ser (S144) and His (H145). The amino acid sequence alignment of the VP2 epitope between EV71 and CA16 showed that it is relatively well conserved with only one variant amino acid sites (residues T141N) among the critical residues. In addition, the VP2 epitope of CA16-190 (the virus used in the passive protection study) is conserved among different genotypes. This finding may also explain why the HBc-E1/2 and HBc-E2 vaccine can cross-react with normal 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