Novel application of Influenza A virus -inoculated chorioallantoic membrane to characterize a NP-specific monoclonal antibody for immunohistochemistry assaying.

Monoclonal antibody (MAb) is widely applied in disease diagnosis. Here we report a MAb, 1 WF-4, against nucleoprotein (NP), its broad response with , and its application in immunohistochemistry (IHC) assay. WF-4 was screened by immunofluorescence assay (IFA). The results showed that its reactivity with baculovirus expressed full-length recombinant NP (rNP) in western blot (WB) and applicability in IHC. Fifteen reference subtypes, H1 to H15, infected chicken embryonated chorioallantoic membranes (CAM) fixed by formalin, were all detectable in WF-4 based IHC. Also, the reactivity of the IHC test with NP from experimentally inoculated H6N1 and from all recent outbreak of H5 subtype avian (AIV) field cases in Taiwan showed positive results. Our data indicate that CAM, the by-product of preparation, is helpful for specific MAb characterization, and that MAb WF-4 recognizes conserved and linear epitopes of NP. Therefore, WF-4 is capable of detecting NP antigen in IHC and may be suitable for developing various tests for diagnosis of , and especially AIV infection.