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Updated: Nov 24, 2025
Immuno-fluorescence Assay of Leptospiral Surface-exposed Proteins
Published on: July 1, 2011
OmpF porin from Yersinia ruckeri as pathogenic factor: Surface antigenic sites and biological properties
Olga Portnyagina1, Dmitry Chistyulin2, Sergey Dyshlovoy3
1G.B Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of Russian Academy of Sciences, 159, Prosp. 100 Let Vladivostoku, Vladivostok, 690022, Russian Federation; School of Natural Sciences, Far Eastern Federal University, 8 Sukhanova St., Vladivostok, 690090, Russian Federation.
Abstract:
Bacterium Yersinia ruckeri as a pathogen induces causative agent of intestinal fish disease called enteric redmouth disease (ERM) is known. In this study, outer membrane OmpF porin from the Y. ruckeri (YrOmpF) has been identified as a pathogenic factor which affects host macrophage activation and life cycle of eukaryotic cells. Using synthetic peptides corresponding to the sequences of the outer loops of YrOmpF L1 loop of the porin is most involved in the structure of B epitopes on the surface of the microbial cell it was found. T epitopes of the isolated YrOmpF trimer not only by linear, but also by discontinuous determinants, which is due to the secondary structure of the protein are represented. It was shown that YrOmpF was twice more cytotoxic to THP-1 cells (human monocytes, cancer cells) in comparison with CHH-1 cells (Oncorhynchus keta cardiac muscle cell, non-cancer cells). It was found YrOmpF induce cell cycle S-phase arrest in both normal CHH-1 and cancer THP-1 cells. In the cancer cells observed effect was most pronounce. In addition, we have observed an induction of apoptosis in THP-1 cell line treated with YrOmpF for 48 h at IC50 (48.6 μg/ml). Significant cytotoxic effect of YrOmpF on primary mouse peritoneal macrophages been detected as well. Of note, co-incubation of macrophages with anti-YrOmpF antibodies could decrease the amount of lactate dehydrogenase, while the number of living cells significantly increased. YrOmpF stimulates the activity of the phagocytic bactericidal systems especially of the oxygen-independent subsystem it was found. Antibodies against YrOmpF decreased MPO release and CP synthesis by peritoneal macrophages and increased their viability.
Insights
Yersinia ruckeri outer membrane OmpF porin (YrOmpF) is a key virulence factor in fish enteric redmouth disease. YrOmpF exhibits cytotoxicity to both normal and cancer cells, inducing cell cycle arrest and apoptosis, particularly in cancer cells.
Area of Science:
- Microbiology
- Immunology
- Cell Biology
Background:
- Yersinia ruckeri is a significant fish pathogen causing enteric redmouth disease (ERM).
- Outer membrane proteins (OMPs) are crucial for bacterial virulence and host-pathogen interactions.
- Understanding the role of specific OMPs in Y. ruckeri pathogenesis is essential for developing control strategies.
Purpose of the Study:
- To identify and characterize the pathogenic role of Yersinia ruckeri outer membrane OmpF porin (YrOmpF).
- To investigate the cytotoxic effects of YrOmpF on different cell types, including immune and cancer cells.
- To explore the immunogenic properties of YrOmpF and its interaction with host immune responses.
Main Methods:
- Synthetic peptide analysis to map B and T epitopes on YrOmpF.
- Cytotoxicity assays using THP-1 (human monocytes) and CHH-1 (Oncorhynchus keta cardiac muscle) cells.
- Cell cycle analysis and apoptosis assays (e.g., IC50 determination).
- Studies on primary mouse peritoneal macrophages, including co-incubation with anti-YrOmpF antibodies.
Main Results:
- YrOmpF was identified as a pathogenic factor affecting macrophage activation and eukaryotic cell cycles.
- YrOmpF demonstrated significant cytotoxicity, being twice as potent against THP-1 cells compared to CHH-1 cells.
- YrOmpF induced S-phase cell cycle arrest in both cell types, with a more pronounced effect in cancer cells.
- Apoptosis was induced in THP-1 cells treated with YrOmpF.
- YrOmpF stimulated phagocytic bactericidal systems, particularly the oxygen-independent subsystem.
- Anti-YrOmpF antibodies reduced macrophage cytotoxicity and inflammatory mediator release (MPO, CP), while enhancing cell viability.
Conclusions:
- YrOmpF is a critical virulence factor in Yersinia ruckeri, contributing to ERM pathogenesis.
- YrOmpF possesses direct cytotoxic effects on host cells, including immune and cardiac cells, with differential impact on normal vs. cancer cells.
- YrOmpF elicits an immune response that can be modulated by antibodies, suggesting potential for immunotherapeutic strategies against Y. ruckeri infections.
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