Abstract: The present invention relates to nucleoprotein (NP) genes of the influenza A and B viruses which were constructed from virion RNA and subsequently expressed in Spodoptera frugiperda (S19) cells using the baculovirus vector, Autographa californica nuclear polyhedrosis virus (AcNPV). Western blot analysis of lysates prepared from S19 cells infected with the recombinant viruses confirmed that the baculovirus-expressed NP antigens were reactive with monoclonal antibodies specific for either type A or B NP and with anti-NP antibodies in human serum samples. Electrophoretic analysis indicated that the expressed influenza NP antigens comigrated with NP purified from influenza A or B virions and that the recombinant NP antigens represented greater than 10% of total protein in infected cells. Dilutions of clarified S19 cell lysates were used as antigens in a standard enzyme immunoassay format to detect serum antibody specific for influenza A or B viruses.

Abstract: The present invention relates to baculovirus-expressed influenza antigens, in particular, to the influenza A membrane protein, M2, expressed from Autographa Californica nuclear polyhedrosis virus (AcNPV). The present invention further relates to a method to increase the yield of baculovirus-expressed M2 proteins in host cells by culturing the recombinant baculovirus infected host cells with an amantadine-like drug. Other aspect of the present invention relate to the use of baculovirus-expressed M2 proteins in reproducible and routine assays for the seradiagnosis of influenza A virus infections as an alternative to the more burdensome complement fixation and hemagglutination tests.