REPLICATION OF WILD-TYPE AND RECOMBINANT AUTOGRAPHA-CALIFORNICA NUCLEAR POLYHEDROSIS-VIRUS IN A CELL-LINE DERIVED FROM MAMESTRA-BRASSICAE

Replication of the baculovirus Autographa californica nuclear polyhedrosis virus (AcNPV) was investigated in a cell line derived from Mamestra brassicae, and was compared with replication in the more commonly used Spodoptera frugiperda cell line (Sf21). Replication of wild-type and recombinant viruses, encoding the genes for beta-galactosidase and chloramphenicol acetyl transferase, were compared. Analysis of the proteins synthesised in the very late phase of gene expression demonstrated that approximately 2-3 fold more polyhedrin or recombinant protein was produced in the M. brassicae cell line. Temporal expression of proteins under polyhedrin promoter control was similar between the two cell lines with the maximum difference in yield being observed at 48 hours post-infection. The M. brassicae cell nuclei contained more polyhedra compared with infected S. frugiperda cells, whereas the extracellular virus titre produced from the M. brassicae cells was approximately 20-fold lower. The bi-phasic life cycle of AcNPV may therefore be biased towards polyhedra production in M. brassicae cells and towards extracellular virus production in the S. frugiperda cells. The usefulness of the M. brassicae cell line for the production of recombinant proteins using baculovirus vectors is discussed.