A new group of anti-lipopolysaccharide factors from Marsupenaeus japonicus functions in antibacterial response.

•A new group of ALFs (MjALF-E1 and E2) was identified in Marsupenaeus japonicus.•Both MjALF-E1 and E2 were upregulated by G+ and G− bacterial challenge.•MjALF-E1 and E2 strongly bind to bacterial cell wall components LPS and PGN.•MjALF-E2 exhibited antimicrobial activity against Gram-negative bacteria.•MjALF-E2 promotes the clearance of bacteria in shrimp.