Fifteen percent reducing SDS-PAGE. (A) Coomassie stained. (B) Immunoblot reacted with rabbit anti-human GM-CSF antibody. Lanes in (A) and (B): lane 1, low molecular weight prestained BioRad protein standards with molecular weights 101 kD, 83 kD, 51 kD, 36 kD, and 29 kD; lane 2, DT388–GM-CSF.