PRV-1 is shed from the cell surface.

293 cells were stably transfected with an expression vector for PRV-1; control cells were not transfected. Cell supernatants were harvested and total cell extracts were prepared from both transfected and untransfected cells. The supernatants were concentrated by centrifugation through a Centricon filter with a molecular weight cut-off of 30 kDa. Concentrated supernatants and cell extracts were analyzed by Western blot using a polyclonal antibody generated against a PRV-1 peptide (amino acids 13-25 of the mature protein; top). As a control, the blot was stripped and reprobed using an antibody against β-actin (bottom).