This recombinant protein is primarily used in immunological research to study immune checkpoint pathways. It serves as a tool to investigate the interaction between Siglec-9 and its ligands on immune cells, particularly in modulating neutrophil and macrophage activity. It is applied in cancer research to understand tumor immune evasion mechanisms, especially in models involving myeloid-derived suppressor cells. The protein is also utilized in binding assays and cellular co-culture systems to evaluate inhibition of inflammatory responses. Its use extends to drug development, where it helps screen potential inhibitors or blocking antibodies targeting the Siglec-9 pathway to enhance anti-tumor immunity.