Pathogenic bacteria defense and complement activation function analysis of Collectin-10 from Hexagrammos otakii

Area of Science:

• Aquaculture immunology
• Innate immunity
• Fish disease resistance

Background:

• Intensive aquaculture of Hexagrammos otakii increases bacterial disease risk.
• Novel antimicrobial molecules are needed to combat these diseases.

Purpose of the Study:

• To identify and characterize a collectin-10 homolog (HoCL-10) in H. otakii.
• To investigate the function of HoCL-10 in innate immunity and host defense.

Main Methods:

• cDNA cloning and sequence analysis of HoCL-10.
• Quantitative reverse transcription PCR (qRT-PCR) for gene expression analysis.
• Recombinant protein expression and functional assays (binding, phagocytosis, migration).
• ELISA and Far-western blot for protein interactions.
• In vivo studies involving antibody injection and bacterial challenge.

Main Results:

• HoCL-10 mRNA expression is highest in liver and skin and induced by lipopolysaccharide (LPS).
• Recombinant HoCL-10 (rHoCL-10) binds to pathogen-associated molecular patterns (PAMPs) and bacteria.
• rHoCL-10 enhances macrophage phagocytosis and migration.
• HoCL-10 interacts with mannose-binding lectin-associated serine proteases (MASP-1, 2) and influences the membrane-attack complex (MAC) in vivo.
• HoCL-10 contributes to host defense against bacterial challenge.

Conclusions:

• HoCL-10 is a key component of the innate immune system in H. otakii.
• HoCL-10 likely functions by opsonizing pathogens and activating the complement system.
• HoCL-10 represents a potential target for improving disease resistance in farmed fish.