Identification and Functional Analysis of ToBPI1/LBP and ToBPI2/LBP in Anti-Bacterial Infection of Trachinotus ovatus

Abstract

Bactericidal/permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) are a group of antibacterial proteins that play an important role in the host’s innate immune defense against pathogen infection. In this study, two BPI/LBPs, named ToBPI1/LBP (1434 bp in length, 478 amino acids) and ToBPI2/LBP (1422 bp in length, 474 amino acids), were identified from the golden pompano. ToBPI1/LBP and ToBPI2/LBP were significantly expressed in immune-related tissues after being challenged with Streptococcus agalactiae and Vibrio alginolyticus. The two BPI/LBPs showed significant antibacterial activity against Gram-negative Escherichia coli and Gram-positive S. agalactiae and Streptococcus iniae. In contrast, the antibacterial activity against Staphylococcus aureus, Corynebacterium glutamicum, Vibrio parahaemolyticus, V. alginolyticus and Vibrio harveyi was low and decreased with time. The membrane permeability of bacteria treated with recombinant ToBPI1/LBP and ToBPI2/LBP was significantly enhanced. These results suggest that ToBPI1/LBP and ToBPI2/LBP may play important immunological roles in the immune response of the golden pompano to bacteria. This study will provide basic information and new insights into the immune response mechanism of the golden pompano to bacteria and the function of BPI/LBP.

Bactericidal Permeability-Increasing Protein (BPI) Inhibits Mycobacterium tuberculosis Growth

“…Recently, it was described that the recombinant BPI of fish Trachinotus ovatus (toBPI), which is homologous to the human protein, efficiently inhibits the growth of Gram-positive bacteria such as Streptococcus agalactia and Streptococcus iniae. Also, toBPI increases bacterial cell membrane permeability like human BPI in Gramnegative bacteria, highlighting the essential role of this protein during infectious processes in different animal species [40]. Furthermore, in an infected human granulocyte model, influenza A virus variants such as H1N1, H3N2, and H5N induce the release of BPI.…”