Virus purification

A method for separating infectious Chikungunya virus particles from non-infectious Chikungunya virus particles comprising precipitating the non-infectious virus particles with protamine.

A method for purifying infectious Chikungunya virus particles, comprising the steps of

• i) providing a crude harvest (a) comprising infectious Chikungunya virus particles, non-infectious Chikungunya virus particles, and impurities, wherein the impurities are generated from growing said virus particles on a cell substrate;
• ii) contacting said crude harvest (a) with an agent comprising protamine to obtain a Chikungunya virus preparation (b) comprising infectious Chikungunya virus particles, wherein the enrichment of infectious Chikungunya virus particles in the virus preparation (b) relative to total Chikungunya virus particles in the crude harvest (a) is in the range of at least 50% to 95%.

A composition for immunization against a Chikungunya virus infection, wherein said composition comprises a Chikungunya virus comprising a deletion mutation in the non-structural protein 3 provided by SEQ ID NO:

• 77 or an immunogenic variant thereof, wherein said immunogenic variant is defined as having at least 80% sequence identity to SEQ ID NO:
• 77;
• and wherein at least 50% of the Chikungunya virus particles in the composition are in the size range of 20-40 nm.

A composition for immunization against a Chikungunya virus infection, wherein said composition comprises a Chikungunya virus comprising a deletion mutation in the non-structural protein 3 provided by SEQ ID NO:

• 77 or an immunogenic variant thereof, wherein said immunogenic variant is defined as having at least 80% sequence identity to SEQ ID NO:
• 77;
• and wherein at least 50% of the Chikungunya virus particles comprised in the composition are infectious Chikungunya virus particles.