Antibody response to the M2 protein of influenza A virus expressed in insect cells

A recombinant baculovirus expressing the M2 protein from influenza A/Ann Arbor/6/60 (H2N2) virus (AA60 virus) was constructed. The expressed M2 protein was recognized by a monoclonal antibody specific for the M2 protein and comigrated with the M2 protein from cells infected with AA60 virus on SDS-polyacrylamide gels. Immunofluorescence studies indicated that the expressed M2 protein was present on the surface of Spodoptera frugiperda (Sf9) cells infected with the recombinant baculovirus. Immunoassays using the expressed M2 protein were able to detect antibodies to the M2 protein in serum samples from humans and ferrets infected with influenza A viruses.