Expanding baculovirus surface display. Modification of the native coat protein gp64 of Autographa californica NPV.

To create a tool for eukaryotic surface display, this approach is aimed at demonstrating a direct modification of the native envelope protein gp64 of Autographa californica NPV without disturbing viral infectivity. Short affinity-tag peptides, the biotin mimic streptagII, and the gp41 amino-acid motif ELDKWA of HIV-1, specific for the human monoclonal antibody 2F5, were engineered into the baculovirus major coat protein gp64 and presented on the viral surface. Two different streptag peptides were inserted at the naturally occurring NotI site at amino-acid 278 of gp64. Additionally, the ten-amino-acid peptide GG-ELDKWA-GG, containing the epitope of mAb 2F5, was introduced into gp64 envelope protein at the same position. In all cases we were able to propagate viable virus-achieving infectious titers in the range of wild-type AcMNPV. Streptag and ELDKWA-epitope surface localization on purified virus particles was demonstrated by flow cytometry and Western blot analysis. We could also show selective retention of mutant viruses by specific interaction between chimeric virions and their target counterparts, recognizing the epitope or the streptag peptide in the viral envelope. These data provide evidence that altering the surface properties of the baculovirus virion could be of value in improving baculovirus display technology and developing new applications.