“…epitope peptide expressed from Escherichia coli (E. coli) protected chickens against IBV infection (Yang et al, 2009a(Yang et al, , 2009b. Furthermore, viral vectored vaccines co-expressing the S1 protein and host cytokines have been reported to induce anti-S1 antibodies (Chen et al, 2010;Shi et al, 2011;Tomley et al, 1987;Wang et al, 2009;Zeshan et al, 2011;Zhang et al, 2012). However, in these reports of protection, recombinant antigen did not provide perfect protection and antibody titers were evaluated only by hemagglutination inhibition (HI) or enzyme-linked immunosorbent assay (ELISA); the respective authors did not indicate whether these antigens retained their native neutralizing antigenicity (Song et al, 1998;Yang et al, 2009aYang et al, , 2009b.…”