Patients immunized with rhGM-CSF as an adjuvant may develop an antibody response to rhGM-CSF. (A) Serum antibody response by ELISA for rhGM-CSF for two patients, CR4723 and MT8463, before starting the vaccine study (○) and after completing all six immunizations (•). (B) Western blot analysis of sera analyzed in (A). Polyacrylamide gel lanes include 0.1 μg lysozyme (negative control), 0.1 μg ovalbumin (negative control), 10 LFU tetanus toxoid (positive control), 0.1 μg yeast-expressed rhGM-CSF, 0.1 μg E. coli-expressed rhGM-CSF. Panels show the antibody responses from the prevaccination sera of patients CR4723 and MT8463 and with the sera obtained after six vaccinations.