N-terminus of M2 protein could induce antibodies with inhibitory activity against influenza virus replication.
New influenza vaccines have been designed based on the fact that the extracellular domain of M2 protein (M2e) is nearly invariant in all influenza A strains. To clarify which exact region of M2e could induce antibodies with inhibitory activities against influenza virus replication, four overlapping peptides covering M2e were synthesized and then coupled to the carrier protein bovine serum albumin through the cysteine of the peptides. After a vaccination course, all these four peptide vaccines could induce high levels of rabbit antibodies with predefined peptide specificity (antibody dilution: 1:6400-1:25600). Besides, the anti-N-terminal antibodies (AS2) reacted strongly with M2e, and reacted weakly with the middle part and C-terminus of M2e. The MDCK assay for cytopathic effect proved that antibodies recognizing the N-terminus of M2e could obviously inhibit replication of influenza A virus (A/wuhan/359/95) and influenza B virus (B/wuhan/321/99) in vitro in a dose-dependent manner, while antibodies recognizing the middle part and the C-terminus of M2e did not show such significant inhibitory activities. Sequence analysis indicates that the first nine N-terminal amino acid residues of M2e are extremely conservative. Just this region containing the first nine amino acid residues could induce antibodies with inhibitory activity against influenza A and influenza B virus replication, suggesting that the N-terminus of M2e may contain an epitope that could induce inhibitory antibodies against influenza virus replication in vitro.
Liu
Wanli
W
Laboratory of Immunology, Research Centre for Medical Science and Department of Biology, Tsinghua University, Protein Science Laboratory of MOE, Beijing 100084, PR China.
Li
Hua
H
Chen
Ying-Hua
YH
D000595:Amino Acid Sequence; D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D002460:Cell Line; D004285:Dogs; D008969:Molecular Sequence Data; D009975:Orthomyxoviridae / Q000276:immunology* / Q000502:physiology; D010446:Peptide Fragments / Q000276:immunology*; D014763:Viral Matrix Proteins / Q000737:chemistry / Q000276:immunology*; D014779:Virus Replication; D000086082:Viroporin Proteins
D000914:Antibodies, Viral; D010446:Peptide Fragments; D014763:Viral Matrix Proteins; C031540:M-protein, influenza virus; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins