Location: Aquatic Animal Health ResearchTitle: Characterization of antiserum immunoglobulin in channel catfish immunized with extracellular proteins of virulent Aeromonas hydrophila
Submitted to: Book of Abstracts World Aquaculture Society
Publication Type: Abstract Only
Publication Acceptance Date: 2/15/2019
Publication Date: 3/7/2019
Citation: Zhang, D., Beck, B.H. 2019. Characterization of antiserum immunoglobulin in channel catfish immunized with extracellular proteins of virulent Aeromonas hydrophila. Book of Abstracts World Aquaculture Society. p. 1226.
Technical Abstract: The emergence of new virulent Aeromonas hydrophila (vAh) strains is of concern in aquaculture industries since the bacteria are capable of causing high mortality of warm-water fishes worldwide. Prophylactic vaccination against vAh is one of the strategies that has been shown to be efficacious for many infectious fish diseases. We previously demonstrated that immunization with extracellular proteins of vAh provided channel catfish with immunity against the establishment of pathogenesis and antiserum in immunized fish was able to recognize specific proteins in the vAh ECP. In this study, we aimed to analyze and characterize agglutinants of ECP and cells of vAh, elicited by anti-ECP serum, to reveal the versatility of vAh antigens and catfish immunoglobulin. Results of this study showed that anti-ECP serum aggregated more than 68 proteins in vAh ECP with molecular weight (MW) ranging from 9 to 95 kDa. Five fish proteins were identified in the ECP agglutinants, including two innate immunity associated proteins (serotransferrin and rhamnose-binding lectin), two immunoglobulin M (IgM) molecules (IgM heavy chain and light chain) and a constitutively-produced protein (warm temperature acclimation protein). IgM was isolated from vAh cell agglutinants (Figure 1). The native IgM was shown to form a tetramer that was responsible for bacterial agglutination. Immunoblotting analysis indicated that the isolated native IgM was able to recognize some proteins in ECP, such as aerolysin and hemolysin. Gene expression analysis by quantitative PCR showed that fish immunized with vAh ECP had more transcripts of genes coding for IgM.