Primary antibodies refer to antibodies used in immunological experiments that can directly recognize and specifically bind to the target antigen. By binding to specific epitopes on the antigen, primary antibodies form antigen-antibody complexes. Their primary role is to detect specific antigen molecules within a sample. Therefore, the selection and quality of the primary antibody directly impacts the experimental results; it provides the foundation for subsequent detection and signal amplification. Primary antibodies are typically generated by injecting the target antigen or antigen fragments into laboratory animals (such as mice, rabbits, goats, etc.) to induce an immune response. In experiments, the primary antibody is applied directly to the sample to bind the target antigen. Common applications include Western Blot (WB), Immunohistochemistry (IHC), Immunocytochemistry (IC/ICC), Flow Cytometry (FCM), and Immunoprecipitation (IP).