Reconstitution of rubella hemagglutinin on liposomes

The hemagglutinin of rubella virus has been purified by differential centrifugation through a sucrose density gradient after disruption of purified virus with Tween 80-ether. The purified isolated hemagglutinin was than adsorbed on liposomes which had been prepared by mixing lecithin and dicetyl phosphate in a 3.5:1 molar ratio. The complex of hemagglutinin adsorbed on the virosomes had a higher sedimentation rate, enabling their separation from free hemagglutinin. It was thus possible to obtain a pure preparation of virosomes by rate zonal centrifugation in a sucrose density gradient containing 0.5 M NaCl. Immunoelectron microscopy showed aggregation of these virosomes with a rubella immune antiserum; this would suggest that the HA subunits are oriented in the same way as on the whole virus.