Stable expression of a foreign protein by a replication-competent rubella viral vector

Area of Science:

• Virology
• Vaccinology
• Molecular Biology

Background:

• Live, attenuated rubella vaccine is established.
• Rubella virus can serve as a viral vector for expressing exogenous antigens.
• Previous limitations included insert size and stability, hindering utility.

Purpose of the Study:

• To overcome limitations in rubella virus as a live viral vector.
• To enhance rubella virus's capacity for expressing foreign antigens.
• To develop a more versatile replicating viral vector system.

Main Methods:

• Engineered a rubella virus hybrid by deleting non-structural protein P150.
• Inserted a model foreign protein (GFP) into the modified rubella virus.
• Assessed stability, replication, and expression of the hybrid virus and foreign protein.

Main Results:

• The modified rubella virus stably expressed Green Fluorescent Protein (GFP) for over 10 passages.
• The hybrid virus replicated normally and continued to express rubella proteins.
• The foreign protein (GFP) was comparable in size to significant viral antigens.
• The virus achieved high titers suitable for potential vaccine development.

Conclusions:

• Deletion of P150 in rubella virus successfully accommodates larger exogenous antigen inserts.
• This engineered rubella virus demonstrates stable expression and replication, enhancing its utility as a viral vector.
• Further development may yield live viral vectors for immunizing against challenging viruses.