Preparation and identification of a novel anti-Enterovirus 71 vaccine of recombinant fusion protein virus-like particle / 中华临床感染病杂志

ABSTRACT

Objective To develop a novel anti-Enterovirus 71 (EV71) vaccine as recombinant virus-like particles.Methods By utilizing the foreign antigen presentation and virus-like particles forming features of Norovirus casipid VP1 P domain (NoVP), two pET-28a (+)-based recombinant expression plasmids containing either NoVP alone or NoVP with three specific epitopes SP55, SP70 and VP2-28 of EV71 capsid proteins tandemly inserted at the surface loop site were constructed and transferred to Escherichia coli.The recombinant fusion proteins of NoVP + EV71-SP55-SP70-VP2-28 and NoVP were induced expression and confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Western blot and transmission electron microscopy (TEM) observation.BALB/C mice were randomly divided into three groupsgroup A immunized with the recombinant fusion protein, group B immunized with NoVP and group C injected with 10 mmol/L Tris plus 20 mmol/L NaCl (pH 9.0).Enzymelinked immunosorbent assay (ELISA) was used to test specific antibodies in the serum of the mice, besides, the serums were mixed with the EV71 H3-TY strain and Vero cells, then specific antibody titer was examined by microneutralization test.One way ANOVA and Bonferroni test were used to analyze data.Results Both recombinant fusion protein and NoVP were expressed in Escherichia coli in inclusion bodies form.SDS-PAGE demonstrated that the relative molecular weights of recombinant fusion protein and NoVP protein were approximately 43 × 103 and 36 × 103, respectively;positive protein band of about 43 × 103 (relative molecular mass) was detected in recombinant fusion protein by Western Blot.Virus-like particles derived from the recombinant fusion proteins were observed under TEM.ELISA showed that absorbance 490 (A490) of mice serum added in SP70 peptide was significantly higher than those of group B and C (F =13.860,P ＜0.05).And microneutralization test demonstrated that the serum from group A was able to neutralize EV71 at a geometric mean titer above 138.Conclusion A novel virus-like particles vaccine against EV71 with good antigenicity and specificity has been prepared, which is able to induce high titer of neutralizing antibody against EV71 in mice.