Protection Of Mice Immunized With Plasmid DNAs Encoding Influenza Virus Nucleoprotein And Matrix Protein

DNA vaccine is a novel vaccine developed from the field of gene therapy.It can elicit persistent humoral and cell mediated immune responses.Plasmid DNA vaccination has shown efficacy against viral, bacterial and parasitic infections,modulating the effects of auto immune and allergic diseases.The DNA vaccine can not only play the role of prevention disease,but also the role of treatment of disease.This article consisting of three parts about our researches on influenza DNA vaccine.Present study is to evaluate the ability of plasmid DNA encoding nucleoprotein(NP)and matrix protein(M)from influenza virus A/PR/8/34 (PR8)(H1N1)to protect BALB/c mice against viral infection by a series of administration.The matrix protein(M)and nucleoprotein(NP)of influenza are of type specificity and have high conservative sequence.So we study NP and M from molecular level to prevent influenza.The NP gene of influenza isolate was 1494bp in length,which encoded 498 amino acids, M1 gene was 759bp in length and encoded 252 amino acids,M2 gene was 322bp in length,encoded 271 amino acids.In the study,we constructed the eukaryotic expression plasmid pCAGGS-M1,M2 and NP, and immuned the BALB/c mice to compare the immunity of them.1)The NP DNA plasmids were injected two times,three times,four times, fives times or six times respectively。2)The M1 DNA plasmids were injected two times,three times,four times,fives times or six times respectively(and the M2 DNA plasmids were injected four times,five times or six times respectively).3)The NP+M1 DNA plasmids were injected two times,three times,four times,fives times or six times respectively。After each immunization,the IgG antibody were detected by ELISA.The result showed that,injection of M1 into muscle of mice could elicite a higher level of specific IgG against M1 than those of groups which were immuned less times.In mice immunized with M1 DNA, showed a lower weight loss compared with those of the negative control mice,and in mice immunezed with NP DNA,showed a lower weight loss compared with those of mice were immunized with M1 DNA,and the mice immunized with NP+M1 were lowest weight loss.Mice immunized with NP+M1 DNA three times showed a 45.5%survival rate.The M2 DNA vaccine can protect poorly against the H1N1 virus for BALB/c mice.The NP gene can provide more than 50%protection.The NP+M1 DNA can provide BALB/c mice more protection than that of NP.Mice immunized with NP+M1 DNA three times showed a 78.6%survival rate.