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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Aquatic Animal Health Strategies

Location: Aquatic Animal Health Research

Title: Apolipoprotein A1 in channel catfish: Transcriptional analysis, antimicrobial activity, and efficacy as plasmid DNA immunostimulant against Aeromonas hydrophila infection

Authors
item Wei Pridgeon, Yuping
item Klesius, Phillip

Submitted to: Fish and Shellfish Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2013
Publication Date: September 6, 2013
Repository URL: http://handle.nal.usda.gov/10113/58420
Citation: Wei Pridgeon, Y., Klesius, P.H. 2013. Apolipoprotein A1 in channel catfish: Transcriptional analysis, antimicrobial activity, and efficacy as plasmid DNA immunostimulant against Aeromonas hydrophila infection. Fish and Shellfish Immunology. 35:1129-1137.

Interpretive Summary: Molecular analysis revealed that apolipoprotein A1 was significantly induced in the anterior kidney of channel catfish after infection with Aeromonas hydrophila. Recombinant protein of apolipoprotein A1 produced in Escherichia coli expression system was found to possess lytic activity against Gram-positive Micrococcus lysodeikticus and Gram-negative A. hydrophila. When recombinant DNA of apolipoprotein A1 was transfected in catfish gill cells, the over-expression of apolipoprotein A1 offered significant protection to gill cells against A. hydrophila infection. When channel catfish were injected with adjuvanted recombinant DNA of apolipoprotein A1 and challenged with a highly virulent A. hydrophila strain AL-09-71 at two days post injection, the recombinant DNA of apolipoprotein A1 offered 100% protection to channel catfish. Our results suggest that the recombinant DNA of apolipoprotein A1 could be used as a novel immunostimulant to offer immediate protection to catfish against A. hydrophila infection.

Technical Abstract: The objectives of this study were to: 1) determine transcriptional profiles of apolipoprotein A1 (ApoA1) in collected channel catfish tissues after infection with A. hydrophila by bath immersion; 2) investigate whether recombinant channel catfish apolipoprotein A1 produced in E. coli expression system possesses any antimicrobial activity against A. hydrophila; 3) evaluate whether recombinant channel catfish apolipoprotein A1 plasmid DNA could be used as immunostimulant to protect fish against A. hydrophila infection. Quantitative PCR revealed that the transcription levels of ApoA1 in infected catfish were significantly (P < 0.05) more induced in the anterior kidney. Recombinant apoA1 produced in Escherichia coli expression system exhibited lytic activity against Gram-positive Micrococcus lysodeikticus and Gram-negative A. hydrophila. When pcDNA3.2-vectored recombinant apoA1 was transfected in channel catfish gill cells G1B, the over-expression of pcDNA-ApoA1 offered significant (P < 0.05) protection to G1B cells against A. hydrophila infection. When channel catfish were intraperitoneally injected with QCDCR adjuvant formulated pcDNA-ApoA1 and challenged with a highly virulent A. hydrophila strain AL-09-71 at two days post injection, pcDNA-ApoA1 injection offered 100% protection to channel catfish. Macrophages of fish injected with pcDNA-ApoA1 produced significantly (P<0.05) higher amounts of reactive oxygen species and nitric oxide than that of fish injected with pcDNA vector alone. Our results suggest that pcDNA-ApoA1 could be used as a novel immunostimulant to offer immediate protection to catfish against A. hydrophila infection.

Last Modified: 8/31/2014