[Preparation and identification of polyclonal antibodies against Moraxella catarrhalis UspA1]

To prepare polyclonal antibodies (PcAb) against UspA1 of Moraxella catarrhalis (Mc), we used bioinformatic analysis to determine the surface exposed region in this protein that holds the antigen epitopes. Then the corresponding coding sequences for this fragment was artificially synthesized according to the codon usage of Escherichia coli. The gene fragment was then subcloned into the prokaryotic expression vector pET-28a(+) and expressed in E. coli rosseta (DE3), and then the recombinant UspA1-His proteins were purified. Two New Zealand white rabbits were immunized with this protein to prepare antiserum. The resulting PcAb was then purified from the antiserum with Protein A affinity column. The results of fluorescence antibody assay, enzyme linked immunosorbent assay and Western blotting analysis showed that the PcAb could specifically recognize the surface exposed region of UspA1 on Mc. The preparation of the PcAb laid a foundation of further development of rapid detection technique for M. catarrhalis.