Evaluation of non-specific immune components from the skin mucus of olive flounder ( Paralichthys olivaceus)

• Published in: Fish & shellfish immunology Vol. 24; no. 4; pp. 479 - 488
• Main Authors: Palaksha, K.J., Shin, Gee-Wook, Kim, Young-Rim, Jung, Tae-Sung
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-04-2008
• Subjects: Alkaline Phosphatase - metabolism; Animals; Antibacterial agglutinin; Bacteria - growth & development; Bacteria - immunology; Caseins - metabolism; Enzyme-Linked Immunosorbent Assay; Esterase; Esterases - metabolism; Flounder - immunology; Hydrolysis; Immunity, Innate - immunology; Immunoblotting; Immunoglobulin M; Immunoglobulin M - immunology; Lysozyme; Marine; Microbial Sensitivity Tests; Mucus - chemistry; Mucus - immunology; Muramidase - metabolism; Paralichthys olivaceus; Pleuronectiformes; Protease; Skin - chemistry; Skin - immunology; Skin mucus; Transferrin; Transferrin - metabolism; Immunoglobulin M; Skin mucus; Transferrin; Esterase; Protease; Antibacterial agglutinin; Lysozyme; Paralichthys olivaceus
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2008.01.005

The innate immune system, particularly the external body surface, plays a frontier role in protecting fish under intensive aquaculture and at prolonged low temperatures from relevant infections due to inadequate adaptive immune responses. In the present study we aimed to understand the mucosal immunity of an economically important mariculture fish, olive flounder (
Paralichthys olivaceus) by evaluating the immune components from its skin mucus. The activities of lysozyme (233.33
±
171.82
units mg
−1), trypsin-like protease (42.84
±
1.249
units mg
−1), alkaline phosphatase (0.376
±
0.005
units mg
−1) and esterase (0.170
±
0.006
units mg
−1) were detected in the skin mucus. Transferrin was identified by MALDI-TOF/MS analysis. ELISA and immunoblot assays using anti-flounder IgM monoclonal antibody showed the presence of a significant level (1.80
±
0.001,
n
=
3) of monomer immunoglobulin M (IgM) with approximate molecular weight of 160 and 25
kDa under non-denaturing and denaturing states, respectively. Skin mucus showed strong antibacterial activity against tested fish pathogenic bacteria. In addition, skin mucus successfully agglutinated (HA titre 2
8), but completely failed to haemolyse, rabbit erythrocytes. In conclusion, the major immune components of the skin mucus, identified in the present study, are possibly involved in the broad spectrum non-specific immunity of olive flounder.