Preliminary Study Of The Epitope Peptide Vaccine Based On EV71 VP1 Gene Sequence In Guizhou

Objective: To make the(EPV)epitope peptide vaccine by using the structural protein VP1 of an enterovirus 71(EV71)strain isolated from children with hand foot and mouth disease(HFMD)in Guizhou and study the immune protective effects on mice.Methods: Peptide fragments was made in vitro by using amino acid sequence of the structural protein VP1 of isolated enterovirus 71 strain which was isolated from throat swab samples of children patients with hand foot mouth disease between 2013 and 2015 in Guizhou area.The epitope peptide vaccine was made by using the polypeptide fragments with better immunogenicity,which were screened out by indirect enzyme linked immunosorbent assay(ELISA)method and Ig G positive serum of children who recovered from EV71 infection.Then the epitope peptide vaccine was used to protect female rats and the control group female rats were given an adjuvant,all female rats and male rats were caged together.Newborn rats were randomly divided into two groups:experimental group and control group which were born by vaccinated and adjuvant-injected female rats,the experimental group infected EV71 virus by intraperitoneal injection,the control group didn't infect EV71 virus.The tissue was harvested from the skeletal muscle,the small intestine and brain of all neonatal rats after two days,they was used to check whether have EV71 virus by reverse transcription polymerase chain Reaction(RT-PCR)and agarose gel electrophoresis and observed the pathological lesion by hematoxylin-eosin staining(H&E).Results: 3 peptide vaccines were made by using polypeptide fragments with better immunogenicity which screened from 19 segments polypeptide fragments with cross sequences that were synthesized by using amino acid sequences of the structural protein VP1 of an isolated enterovirus 71 strain in Guizhou area.All tissue of each group was used to detect the viral nucleic acid by RT-PCR and agarose gel electrophoresis,it showed that EV71 virus can be detected in infected groups,cannot be detected in uninfected groups.The pathological lesion of all tissue by H&E showed that no obvious inflammatory lesion in each tissue was found in uninfected groups,varying degree of inflammatory lesion in each tissue was found in infected groups,and the level of inflammatory lesion in vaccinated groups was lower than adjuvant-injected groups,there was no significant difference in each tissue between the three vaccinated groups.Conclusion: The three kinds of VP1 antigen epitope polypeptide vaccines have good immunogenicity were successfully prepared.Animal experiments showed that three kinds of vaccine immunized female rats all produced good immune protection effect in Neonatal rats,A new epitope peptide vaccine based on EV71 VP1 gene sequence was successfully created.