Construction of a chimeric secretory IgA and its neutralization activity against avian influenza virus H5N1

Secretory immunoglobulin a (siga) acts as the first line of defense against respiratory pathogens. in this assay,the variable regions of heavy chain (vh) and light chain (vl) genes from a mouse monoclonal antibody against h5n1 were cloned and fused with human iga constant regions. the full-length chimeric light and heavy chains were inserted into a eukaryotic expressing vector and then transfected into cho/dhfr-cells. the chimeric monomeric iga antibody expression was confirmed by using elisa,sds-page,and western blot. in order to obtain a dimeric secretory iga,another two expressing plasmids,namely,pcdna4/his a-igj and pcdna4/his a-sc,were cotransfected into the cho/dhfr-cells. the expression of dimeric siga was confirmed by using elisa assay and native gel electrophoresis. in microneutralization assay on 96-well immunoplate,the chimeric siga showed neutralization activity against h5n1 virus on mdck cells and the titer was determined to be 1: 64. on preadministrating intranasally,the chimeric siga could prevent mice from lethal attack by using a/vietnam/1194/04 h5n1 with a survival rate of 80%. so we concluded that the constructed recombinant chimeric siga has a neutralization capability targeting avian influenza virus h5n1 infection in vitro and in vivo. © 2014 cun li et al.