*3.2. Characterization of the mAbs*

According to the antiserum results, the mouse with high sensitivity and inhibitory rate was selected for the cell fusion experiment. At present, PEG 4000 and PEG 1450 are commonly used for cell fusion. Due to the large molecular weight of PEG 4000, the cells lost water faster and fused more violently, causing cell injury. In contrast, the PEG 1450

fusion process was mild and achieved perfect results. After four subclones, PBA-BSA-A3 was used as the immunogen, and four specific mAbs against PYR and BaP were obtained. They were named 4A3, 4D6, 5D8 and 6H4, and the results are provided in Table S2. The 4D6 mAb, which was selected for subsequent experiments because it exhibited the highest sensitivity, had an optimum dilution of 20,000 and an IC50 of 5.3 ng/mL. The results of mouse monoclonal antibody type identification indicated that the antibody subtypes were all IgG1 (Figure S2).
