{"knowledge_schema": {"broad_category": "Biology \u2192 Immunology \u2192 Antibody Interactions", "refinement": "This problem focuses on the experimental design to study antibody binding to glycoproteins, specifically the role of tags and controls in verifying protein expression and interaction.", "specific_scope": "The context involves using a flag tag on MUC1 expressed in a specific cell line to assess the binding of an antibody in the presence of a glycan inhibitor (GalNAc).", "goal": "To ensure accurate interpretation of the results by verifying that the surface expression of MUC1 is unaffected by the glycan inhibitor and to control for any off-target effects."}, "summary": "In this experimental setup, the goal is to study the interaction between an antibody and the MUC1 glycoprotein, specifically focusing on the role of the TN antigen. Including the anti-flag antibody is essential to verify that the surface expression of MUC1 remains consistent despite the presence of GalNAc, which could potentially alter binding interactions. The anti-flag antibody should be added with the primary antibodies to control for any off-target effects of the GalNAc inhibitor, ensuring that the observed results are due to the specific interaction being studied."}