Cathelicidin Antimicrobial Peptide (CAMP) is a cationic host defense peptide predominantly expressed in neutrophils, epithelial cells, and keratinocytes, with a conserved cathelin domain at the N-terminus and a variable antimicrobial domain at the C-terminus. It exerts broad-spectrum antimicrobial activity against bacteria, fungi, and viruses by disrupting microbial cell membranes, and also modulates the host immune response by regulating cytokine secretion, promoting immune cell recruitment, and enhancing wound healing. CAMP plays a critical role in innate immunity, bridging the gap between innate and adaptive immune systems. Abnormal CAMP expression is associated with inflammatory disorders, skin diseases, and infectious pathologies, making it a promising target for developing antimicrobial therapeutics. CAMP interacts with lactoferrin (LTF) to synergistically enhance antimicrobial efficacy and immune regulatory functions.Thus a functional ELISA assay was conducted to detect the interaction of recombinant mouse CAMP and recombinant human LTF. Briefly, CAMP was diluted serially in PBS with 0.01% BSA (pH 7.4). Duplicate samples of 100 μl were then transferred to LTF-coated microtiter wells and incubated for 1h at 37℃. Wells were washed with PBST and incubated for 1h with anti-CAMP 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 CAMP and recombinant human LTF was shown in Figure 1, the EC50 for this effect is 0.612µg/mL.