Effects of extracellular products from the pathogenic Vibrio aestuarianus strain 01/32 on lethality and cellular immune responses of the oyster Crassostrea gigas
International audience Vibrio aestuarianus strain 01/32 was previously shown to be pathogenic to Crassostrea gigas juveniles. To investigate virulence mechanisms of this pathogen, we studied the toxicity to oysters of its extracellular products (ECPs). ECPs displayed lethality to animals, with a LD5...
Published in: | Developmental & Comparative Immunology |
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Main Authors: | , , , , |
Other Authors: | , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2006
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Subjects: | |
Online Access: | https://hal.science/hal-00629874 https://doi.org/10.1016/j.dci.2005.05.003 |
Summary: | International audience Vibrio aestuarianus strain 01/32 was previously shown to be pathogenic to Crassostrea gigas juveniles. To investigate virulence mechanisms of this pathogen, we studied the toxicity to oysters of its extracellular products (ECPs). ECPs displayed lethality to animals, with a LD50 value of 3.3 mg/g body weight. To determine the oyster cellular immune responses were induced by these ECPs, we further examined in vitro their effects on C. gigas hemocytes, using flow cytometric-based hemocyte assays. Treatment of hemolymph with ECPs caused a significant inhibition of hemocyte phagocytosis and adhesive capabilities. In contrast, the pathway of reactive oxygen species production was enhanced by higher ECP concentrations. Exposure of hemocytes to live bacteria induced no changes in hemocyte parameters. Together, these results suggest that V. aestuarianus strain 01/32 secretes one or more factors which may play an important role in the pathogenicity of this microorganism, and which display immunosuppressant activities on hemocyte functions. |
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