The char of migration inhibitory factor and Cathepsin B from Asian swamp eel (Monopterus albus) and their response to challenge with Aeromonas hydrophila

Abstract

Aeromonas hydrophila causes sepsis and is responsible for significant economic losses in Asian finless eel (Monopterus albus) aquaculture. Previous studies have found that macrophage migration inhibitory factor (MIF) and Cathepsin B (CTSB) may be expressed in many vertebrate tissues and organs. However, there have been no reports discussing the importance of MIF and CTSB in Asian swamp eel. The complete ORF sequences of MAMIF and MACTSB were found to be 348 and 993 bp, respectively. The adaptive analysis showed that the sequences of MAMIF and MACTSB were highly conserved, and only two positive selection sites were identified in MAMIF. Quantitative real time polymerase chain reaction (qRT-PCR) demonstrated that MAMIF and MACTSB genes were expressed in all tissues evaluated with the highest expression occurring in the head kidney, spleen and liver. Challenge with Aeromonas hydrophila resulted in a significant increase in the expression of MAMIF and MACTSB in skin, liver, head kidney and spleen that peaked at 12-h post-infection. The results show that MAMIF and MACTSB play important roles in the immune function of Monopterus albus.