Immunolocalization of rPLG in stable transfectants. Untransfected CHO-K1 cells (A) and stably transfected CHO-K1 cells expressing rR561S (B) or rR561S + S572P (C) were fixed, permeabilized, and reacted with rabbit polyclonal anti-human PLG antibody. The cells then were incubated with biotinylated anti-rabbit IgG and immunostained using an ABC kit.