Electrophoretic analysis of recombinant FXII proteins. Vaccinia virus-infected HepG2 cells were metabolically labeled and the culture media were immunoprecipitated and electrophoresed as indicated in Materials and Methods. Culture media from HepG2 cells infected with vFXII (lane 1) or with vFXII.▵19 (lane 2) immunoprecipitated with MoAb KOK5; culture media from HepG2 cells infected with vFXII (lane 3) or with vFXII.▵19 (lane 4) immunoprecipitated with MoAb B7C9.