FIG. 2.

The E2 SP is required for RLP secretion. Capsid protein constructs with an E2, VSV G, or CD8 SP were cotransfected with the E2E1 expression plasmid into COS cells. Forty-eight hours posttransfection, media from the transfected cells were precleared of cell-associated material and then the medium samples (M) were subjected to centrifugation at 100,000 × g to pellet RLPs. Cell lysates (C) were also prepared from the transfected cells. Lysates (C) and membrane pellets (M) were subjected to SDS-PAGE, transferred to polyvinylidene difluoride membranes, and immunoblotted with anticapsid antibody, followed by enhanced chemiluminescence detection. Capsid proteins which are incorporated into secreted RLPs are detected in the membrane pellet fractions.