Antimicrobial Activity of Human C-Type Lectin Domain Family 3 Member A (CLEC3A)

C-type lectins (CTLs) are a group of proteins that play a crucial role in immunological functions. With the rise of antibiotic-resistant bacteria, CTLs have emerged as a potential alternative to traditional antibiotics and antimicrobial peptides (AMPs), the latter exhibiting limited application due to their low biostability. In this study, we used viable count assays to investigate the antimicrobial activity of the human C-type Lectin Domain Family 3 Member A (CLEC3A) and its two protein domains, CLEC3A Ex23 and CLEC3A Ex3, against gram-positive and gram-negative bacteria. Additionally, using immunoblot analysis, we assessed the biostability of CLEC3A and its protein domains in bacterial supernatant and murine serum. Our findings demonstrate that CLEC3A, CLEC3A Ex23, and CLEC3A Ex3 possess antimicrobial activity against gram-positive Staphyloccocus aureus and gram-negative Pseudomonas aeruginosa. CLEC3A is more effective against P. aeruginosa than the well-investigated antimicrobial peptide LL-37. Furthermore, CLEC3A and its domains have low sensitivity to bacterial and serum proteases, making them more advantageous for systemic application than most AMPs. In conclusion, our research has demonstrated that CLEC3A is not only a precursor of AMPs but also an antimicrobial protein itself, with favorable characteristics for therapeutic applications.