ABSTRACT
To construct a recombinant T7 phage expressing matrix protein 2 ectodomain (M2e) peptides of avian influenza A virus and test immunological and protective efficacy in the immunized SPF chickens. M2e gene sequence was obtained from Genbank and two copies of M2e gene were artificially synthesised, the M2e gene was then cloned into the T7 select 415-1b phage in the multiple cloning sites to construct the recombinant phage T7-M2e. The positive recombinant phage was identified by PCR and sequencing, and the expression of surface fusion protein was confirmed by SDS-PAGE and Western-blot. SPF chickens were subcutaneously injected with 1 X 10(10) pfu phage T7-M2e, sera samples were collected pre- and post-vaccination, and were tested for anti-M2e antibody by ELISA. The binding capacity of serum to virus was also examined by indirect immunofluorescence assay in virus- infected CEF. The immunized chickens were challenged with 200 EID50 of H9 type avian influenza virus and viral isolation rate was calculated to evaluate the immune protective efficacy. A recombinant T7 phage was obtained displaying M2e peptides of avian influenza A virus, and the fusion protein had favorable immunoreactivity. All chickens developed a certain amount of anti-M2e antibody which could specially bind to the viral particles. In addition, the protection efficacy of phage T7-M2e vaccine against H9 type avian influenza viruses was 4/5 (80%). These results indicate that the recombinant T7 phage displaying M2e peptides of avian influenza A virus has a great potential to be developed into a novel vaccine for the prevention of avian influenza infection.
Subject(s)
Animals , Antibodies, Viral , Blood , Bacteriophage T7 , Genetics , Allergy and Immunology , Metabolism , Chickens , Enzyme-Linked Immunosorbent Assay , Gene Expression Regulation, Viral , Immunization , Influenza A virus , Genetics , Allergy and Immunology , Influenza Vaccines , Allergy and Immunology , Influenza in Birds , Allergy and Immunology , Metabolism , Peptides , Genetics , Allergy and Immunology , Metabolism , Polymerase Chain Reaction , Recombinant Fusion Proteins , Specific Pathogen-Free Organisms , Viral Matrix Proteins , Genetics , Allergy and Immunology , MetabolismABSTRACT
M2e gene of three copies for H5N1 subtype AIV was synthesized and fused with human mycobacterium tuberculosis hsp70 gene.The fused gene was cloned into the prokaryotic expression vector to get pET-3M2e and pET-3M2e-hsp70.Recombinant protein r3M2e and r3M2e-hsp70 were successfully expressed induced with IPTG and purified with Ni2+-NTA collumn.Following that,the immunity of the recombinant protein was analysized with Western blot.20-day-old AIV non-immunized chickens were vaccined with r3M2e and r3M2e hsp70,at the same time,Trx and KLH-M2e inoculated chickens were served as vector and positive controls.Two weeks after the primary vaccination,every group was boosted with the same vaccine as in the primary vaccination.The humoral immunity of the vaccined chickens was evaluated with antibody detection against M2e,cytopathic suppression test,and indirect fluorescence assay.The cellular immunity was estimated according to lymphocyte subtype analysis with flow cytometry and M2e specific cytokine detection.Four weeks after the boost vaccine,all groups were challenged with 100EID50 AIV of H9N2 subtype,and the virus from swabs was detected with Real-time PCR.Results indicated that r3M2e hsp70 vaccined chicken developed the better humoral and cellular immune response,also,made a better performance compared with r3M2e vaccined group in virus challenge.
ABSTRACT
Based on the gene sequence of AIV matrix protein 2(M2) and two cytotoxic T-lymphocyte epitopes derived from nucleoprotein,the prokaryotic expression vector pET-3M2e-NP1-NP2 was constructed.The target gene was expressed in the solvable form in BL21(DE3) when induced with 1.0 mmol/L IPTG and Western blot analysis showed that the expression product had good immunogencity.Purified fusion protein was mixed with various amount of adjuvant,including Freund's,Vash oil and chitosan,and then immunized 20-day-old chicken by intramuscular injection and boosted 3weeks later.Blood samples were collected weekly following the primary vaccination.The anti-M2e antibody was detected with ELISA method with the synthesized peptide as coated antigen;the neutralizing ability of anti-serum was evaluated on MDCK cell line and chick embryo,the CD4+ and CD8+ T lymphocyte amounts in peripheral blood of immunized chicken was measured by flow cytometry.Results showed that the fusion protein can induce immunological reaction,and the antibody can bind with the viral M2 protein that expressed on the surface of MDCK cells.Flow cytometry result showed that CD4+ and CD8+ T lymphocyte in peripheral blood increased obviously following immunization(P