FIG. 4.

Folding of TBE virus envelope proteins expressed as a polyprotein precursor. COS-1 cells were transfected with a recombinant plasmid encoding prM and E. At 24 h posttransfection, the folding of prM and E was assayed by a pulse-chase approach, followed by immunoprecipitation of the postnuclear supernatants with a polyclonal antiserum recognizing both prM and E (A) or MAb specific for prM and E, as indicated (B and C). The immunoprecipitates were analyzed by nonreducing and reducing SDS-PAGE. Positions of the proteins are marked at the left, and molecular size standards are indicated on the right in kilodaltons.