Kidney Injury Molecule 1, also known as Kim1 or TIM-1, is a transmembrane glycoprotein encoded by the HAVCR1 gene. It is minimally expressed in healthy kidneys but markedly upregulated following renal injury, making it a sensitive biomarker for acute kidney injury (AKI). Kim1 plays a dual role in kidney damage: it promotes phagocytosis of apoptotic cells and cellular debris, aiding tissue repair, while its persistent expression may contribute to fibrosis and chronic kidney disease (CKD). Structurally, Kim1 contains an immunoglobulin-like domain and a mucin-rich extracellular region. Beyond AKI, Kim1 is implicated in immune regulation and viral entry . Its diagnostic and therapeutic potential is actively researched.Besides,Death receptor 5 (DR5) has been identified as an interactor of Kim1, thus a functional binding ELISA assay was conducted to detect the interaction of recombinant mouse Kim1 and recombinant rat DR5. Briefly, Kim1 was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to DR5-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-Kim1 pAb, then aspirated and washed 3 times. After incubation with HRP labelled secondary antibody for 1h at 37℃, wells were aspirated and washed 5 times. With the addition of substrate solution, wells were incubated 15-25 minutes at 37℃. Finally, add 50 µL stop solution to the wells and read at 450/630nm immediately. The binding activity of recombinant mouse Kim1 and recombinant rat DR5 was shown in Figure 1, the EC50 for this effect is 0.36 µg/mL.