A GP64-null baculovirus pseudotyped with vesicular stomatitis virus G protein

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• The Autographa californica multiple nucleopolyhedrovirus (AcMNPV) GP64 protein is crucial for viral entry and cell-to-cell spread.
• GP64-null viruses exhibit defects in budded virion (BV) assembly and production, hindering their propagation.

Purpose of the Study:

• To investigate whether a heterologous viral envelope protein, vesicular stomatitis virus G protein (VSV-G), can pseudotype GP64-null baculoviruses.
• To determine if VSV-G pseudotyped viruses are infectious and capable of cell-to-cell movement.

Main Methods:

• Generation of a stably transfected insect Sf9 cell line (Sf9(VSV-G)) inducibly expressing VSV-G.
• Infection of Sf9(VSV-G) and Sf9 cells with GP64-null baculovirus (vAc(64-)).
• Monitoring plaque formation, viral propagation, and identification of pseudotyped virions and recombinant viruses.

Main Results:

• vAc(64-) formed plaques on Sf9(VSV-G) cells but not on Sf9 cells, indicating VSV-G mediated infectivity.
• Passage on Sf9(VSV-G) cells produced pseudotyped vAc(64-) containing VSV-G protein.
• Pseudotyped vAc(64-) showed delayed cell-to-cell propagation compared to wild-type AcMNPV, with titers up to 10(7) IU/ml.
• A recombinant virus acquiring the VSV-G gene demonstrated productive infection and propagation in Sf9 cells.

Conclusions:

• VSV-G can functionally complement GP64-null baculoviruses, facilitating BV assembly, budding, and cell-to-cell spread.
• VSV-G pseudotyping enables the production of infectious GP64-null baculoviruses.
• This study provides insights into baculovirus assembly and budding mechanisms and potential for viral vector development.