[Objective] The aim was to study characteristics of the NDV-HN protein epitope in the animal immune response.[Method] A pair of specific primers was designed according to the HN gene sequence and multiple clone sites of vector PGEX-4T-1;and then PCR amplification was conducted by using a recombinant plasmid as template.The amplified fragment was inserted into pGEX-4T-1 to construct a new recombinant plasmid.After the recombinant plasmid was identified,it was expressed in prokaryotic cells.The monoclonal ant...