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Zhang M, Yan X, Wang CB, Liu WQ, Wang Y, Jing H, Wang B, Yang K, Chen ZY, Luan YY, Wang GH. Molecular characterization, antibacterial and immunoregulatory activities of liver-expressed antimicrobial peptide 2 in black rockfish, Sebastes schlegelii. FISH & SHELLFISH IMMUNOLOGY 2024; 147:109467. [PMID: 38423489 DOI: 10.1016/j.fsi.2024.109467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/24/2024] [Accepted: 02/25/2024] [Indexed: 03/02/2024]
Abstract
LEAP2 (liver expression antimicrobial peptide 2), is an antimicrobial peptide widely found in vertebrates and mainly expressed in liver. LEAP2 plays a vital role in host innate immunity. In teleosts, a number of LEAP2 homologs have been reported, but their in vivo effects on host defense are still limited. In this study, a LEAP2 homolog (SsLEAP2) was identified from black rockfish, Sebastes schlegelii, and its structure, expression as well as biological functions were analyzed. The results showed that the open reading frame of SsLEAP2 is 300 bp, with a 5'- untranslated region (UTR) of 375 bp and a 3' - UTR of 238 bp. The deduced amino acid sequence of SsLEAP2 shares the highest overall identity (96.97%) with LEAP2 of Sebastes umbrosus. SsLEAP2 possesses conserved LEAP2 features, including a signal peptide sequence, a prodomain and a mature peptide, in which four well-conserved cysteines formed two intrachain disulphide domain. The expression of SsLEAP2 was highest in liver and could be induced by experimental infection with Listonella anguillarum, Edwardsiealla piscicida and Rock bream iridovirus C1 (RBIV-C1). Recombinant SsLEAP2 (rSsLEAP2) purified from Escherichia coli was able to bind with various Gram-positive and Gram-negative bacteria. Further analysis showed that rSsLEAP2 could enhance the respiratory burst activity, and induce the expression of immune genes including interleukin 1-β (IL-1β) and serum amyloid A (SAA) in macrophages; additionally, rSsLEAP2 could also promote the proliferation and chemotactic of peripheral blood lymphocytes (PBLs). In vivo experiments indicated that overexpression of SsLEAP2 could inhibit bacterial infection, and increase the expression level of immune genes including IL-1β, tumor necrosis factor ligand superfamily member 13B (TNF13B) and haptoglobin (HP); conversely, knock down of SsLEAP2 promoted bacterial infection and decreased the expression level of above genes. Taken together, these results suggest that SsLEAP2 is a novel LEAP2 homolog that possesses apparent antibacterial activity and immunoregulatory property, thus plays a critical role in host defense against pathogens invasion.
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Affiliation(s)
- Min Zhang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, Shandong Province, 266109, China
| | - Xue Yan
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Chang-Biao Wang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Wen-Qing Liu
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Yue Wang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Hao Jing
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Bing Wang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Kai Yang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Zi-Yue Chen
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Yu-Yu Luan
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China
| | - Guang-Hua Wang
- School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong Province, 266109, China.
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2
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Zhang J, Zhou D, Zhang B, Li X, Jiao X. Tetraspanin CD53 regulates peripheral blood leucocytes vitality and pathogen infection in turbot (Scophthalmus maximus). FISH & SHELLFISH IMMUNOLOGY 2024; 146:109412. [PMID: 38296007 DOI: 10.1016/j.fsi.2024.109412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 01/22/2024] [Accepted: 01/27/2024] [Indexed: 02/19/2024]
Abstract
Cluster of differentiation 53 (CD53) also known as OX44 or tetraspanin 25 (TSPAN25) is a glycoprotein belonging to the tetraspanin family. Members of the tetraspanin family are characterized by four transmembrane domains, including intracellular N- and C-termini, and small and large extracellular domains. Currently, the function of CD53 in teleost is not well understood. In this study, we identified a CD53 (named SmCD53) from turbot (Scophthalmus maximus) and examined its expression and biological activity. SmCD53 contained 231 amino acid residues and was predicted to be a tetraspanin with small and large extracellular domains. SmCD53 expression was observed in different tissues, particularly in immune-related organs. Experimental infection with bacterial or viral pathogen significantly up-regulated SmCD53 expression in a time-dependent manner. Immunofluorescence microscopy analysis showed that SmCD53 was localized on the surface of PBL and was recognized by antibody against its large extracellular domain. Ligation of SmCD53 onto PBLs with antibodies suppressed the respiratory burst activity, inflammatory reaction, and enhanced cell viability. SmCD53 knockdown significantly enhanced bacterial dissemination and proliferation in turbot. Overall, these results underscore the importance of CD53 in the maintenance of the function and homeostasis of the immune system.
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Affiliation(s)
- Jian Zhang
- School of Ocean, Yantai University, Yantai, China.
| | - Dandan Zhou
- School of Ocean, Yantai University, Yantai, China
| | - Binzhe Zhang
- School of Ocean, Yantai University, Yantai, China
| | - Xuepeng Li
- School of Ocean, Yantai University, Yantai, China
| | - Xudong Jiao
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.
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Feng JX, Liu L, Wang HY, Zhang J, Li XP. A soluble TLR5 is involved in PBLs activation and antibacterial immunity via TLR5M-MyD88-signaling pathway in tongue sole Cynoglossus semilaevis. Int J Biol Macromol 2023; 230:123208. [PMID: 36634796 DOI: 10.1016/j.ijbiomac.2023.123208] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/11/2023]
Abstract
In higher vertebrates, there is only a membranal TLR5 (TLR5M), which is crucial for host defense against microbes via MyD88 signaling pathway. In teleost, both TLR5M and soluble TLR5 (TLR5S) are identified, whereas the antibacterial mechanism of TLR5S is largely unknown. In this study, we studied the immune antibacterial mechanism of Cynoglossus semilaevis TLR5S homologue (named CsTLR5S). CsTLR5S, a 71.1 kDa protein, consists of 649 amino acid residues and shares 41.7 %-57.8 % overall sequence identities with teleost TLR5S homologues. CsTLR5S contains a single extracellular domain (ECD) composed of 12 leucine-rich repeats. CsTLR5S expression was constitutively identified and upregulated by bacterial infection in tissues. In vitro recombinant CsTLR5S (rCsTLR5S) could interact with bacteria and tongue sole rTLR5M (rCsTLR5M). Furthermore, rCsTLR5S could bind to the membranal CsTLR5M of peripheral blood leukocytes (PBLs), which led to enhancing the activity and the antibacterial role of PBLs via Myd88-NF-κB pathway. In vivo rCsTLR5S could activate the Myd88-NF-κB pathway, facilitate the release of proinflammatory cytokines, and enhance the host antibacterial response against Vibrio harveyi. Moreover, the knockdown of CsTLR5M or the Myd88 inhibitor could significantly suppress the antibacterial effect of rCsTLR5S. Collectively, our findings added important insights into the TLR5S immune antibacterial property in a TLR5M-MyD88-dependent manner.
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Affiliation(s)
- Ji-Xing Feng
- School of Ocean, Yantai University, Yantai, China
| | - Ling Liu
- School of Ocean, Yantai University, Yantai, China
| | - Hong-Ye Wang
- School of Ocean, Yantai University, Yantai, China
| | - Jian Zhang
- School of Ocean, Yantai University, Yantai, China.
| | - Xue-Peng Li
- School of Ocean, Yantai University, Yantai, China.
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Wang Y, Xu H, Sun B. Cathepsin H and cathepsin B of Cynoglossus semilaevis are involved in anti-bacterial immunity against Edwardsiella tarda. FISH & SHELLFISH IMMUNOLOGY 2023; 134:108594. [PMID: 36754156 DOI: 10.1016/j.fsi.2023.108594] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 02/02/2023] [Accepted: 02/04/2023] [Indexed: 06/18/2023]
Abstract
Cathepsin H and Cathepsin B are two lysosomal cysteine proteases participating in various physiological processes including immune responses. In fish, the functional roles of Cathepsin H and Cathepsin B during bacterial infection are less understood. In a previous work, we characterized a Cathepsin B homologue (CsCatB) of half-smooth tongue sole (Cynoglossus semilaevis), an economically valuable fish species in China. In this report, we identified a Cathepsin H homologue (CsCatH) from C. semilaevis. In healthy tongue sole, the transcriptional expression of CsCatH was detected in nine different tissues. Laser scanning confocal microscopic analysis showed that ectopically expressed CsCatH and CsCatB were co-localized with the lysosome. Upon infection by Edwardsiella tarda, a significant fish pathogen which caused a severe fish disease termed edwardsiellosis, the expressions of CsCatH and CsCatB were remarkedly upregulated. The knockdown of CsCatH and CsCatB significantly increased the replication of E. tarda and mitigated E. tarda-induced apoptosis in tongue sole tissues. These findings revealed the importance of CsCatH and CsCatB in anti-bacterial immunity of tongue sole.
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Affiliation(s)
- Yilong Wang
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Hang Xu
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Boguang Sun
- CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, China.
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5
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Li MF, Zhang HQ, Sun JS. A novel C1qDC (PoC1qDC) with a collagen domain in Paralichthys olivaceus mediates complement activation and against bacterial infection. FISH & SHELLFISH IMMUNOLOGY 2023; 132:108472. [PMID: 36470404 DOI: 10.1016/j.fsi.2022.108472] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/08/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
Complement C1q domain containing protein (C1qDC) is a vital recognition molecule and has an important effect on immunity. The C1qDCs exhibit opsonic activity in fish, while the mechanisms of C1qDCs in activation complement still remain unclear. This study explored immunological characteristics of a C1qDC from Japanese flounder (Paralichthys olivaceus) (PoC1qDC). PoC1qDC consists of 296 amino acid residues, possessing a collagen domain and a C1q domain. According to our results, PoC1qDC was expressed in 9 diverse tissue samples and showed up-regulation after bacterial challenge. Recombinant PoC1qDC (rPoC1qDC) activated normal serum bactericidal and hemolytic activities by interaction with Japanese flounder IgM, but not enhanced the complement activity of C3-depeleted serum. rPoC1qDC was significantly bound to various bacterial species and agglutination activity against Edwardsiella piscicida and Streptococcus iniae. Furthermore, rPoC1qDC showed direct interaction with peripheral blood leucocytes while enhancing phagocytic and chemotactic activity. When PoC1qDC was overexpressed in Japanese flounder before E. piscicida infection, bacterial replication was significantly inhibited in fish tissues. Consistently, when PoC1qDC expression in Japanese flounder was knocked down, bacterial replication was significantly enhanced. The above findings first suggested the role of PoC1qDC in teleost in mediating complement activation by interaction with IgM, which can positively influence bacterial infection.
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Affiliation(s)
- Mo-Fei Li
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin, 300387, China
| | - Hong-Qiang Zhang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin, 300387, China
| | - Jin-Sheng Sun
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin, 300387, China.
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6
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Kim TH, Don Hwang S, Kim SJ, Kim MS, Choi HS, Han HJ. Efficacy of a recombinant M-like protein, SimA as a subunit vaccine candidate against Streptococcus parauberis infection in olive flounder, Paralichthys olivaceus. FISH & SHELLFISH IMMUNOLOGY 2022; 131:1092-1100. [PMID: 36257554 DOI: 10.1016/j.fsi.2022.10.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/12/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Streptococcus parauberis, a gram-positive cocci, causes bacterial disease in farmed fish. The recent increase in S. parauberis infection in aquatic farms in South Korea has justified the importance of vaccine development for the prevention of this disease. In this study, we evaluated the effect of subunit vaccines prepared from recombinant M-like protein (SimA) and fibrinogen-binding protein (FBP) candidates with an aluminum hydroxide adjuvant against S. parauberis infection in olive flounder Paralichthys olivaceus. For the in vivo experiment, fish (average length, 7.18 cm; average weight, 3.5 g) were injected intraperitoneally with: phosphate buffer saline (PBS, group 1), PBS/aluminum hydroxide (group 2), FBP/aluminum hydroxide (group 3), SimA/aluminum hydroxide (group 4), and SimA/FBP/aluminum hydroxide (group 5). After 3 weeks, the fish in each group were boosted using PBS (group 1 and 2), FBP (group 3), SimA (group 4), and SimA/FBP (group 5) without adjuvant. We found that the relative percent survival of fish after S. parauberis exposure in group 2, 3, 4, and 5 was 6.25%, 18.75%, 50%, and 12.5%, respectively, whereas the mortality in groups 1 was 80%, respectively. We performed Western blot, ELISA, and quantitative real time RT-PCR (qRT-PCR) after vaccination to investigate the further efficacy of the vaccine. Western blot and ELISA of vaccinated fish serum confirmed the production of specific antibodies against SimA and FBP. Furthermore, results of qRT-PCR showed that recombinant protein SimA induced a remarkably specific-antibody response compared with that in FBP or control and increased the expression of various immune response-related genes including interleukin-8 (IL-8), toll-like receptor 2 (TLR2), tumor necrosis factor-α (TNF-α), CD4-1, and MHC II. Thus, these results indicate that SimA is a potent vaccine candidate for protection against S. parauberis infection.
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Affiliation(s)
- Tae-Ho Kim
- Pathology Division, National Institute of Fisheries Science, Busan, 46083, South Korea
| | - Seong Don Hwang
- Division of Convergence on Marine Science, Korea Maritime and Ocean University, 727 Taejong-ro, Yeongdo-gu, Busan, 49112, Republic of Korea
| | - Soo-Jin Kim
- Pathology Division, National Institute of Fisheries Science, Busan, 46083, South Korea
| | - Myoung-Sug Kim
- Pathology Division, National Institute of Fisheries Science, Busan, 46083, South Korea
| | - Hye-Sung Choi
- Pathology Division, National Institute of Fisheries Science, Busan, 46083, South Korea
| | - Hyun-Ja Han
- Pathology Division, National Institute of Fisheries Science, Busan, 46083, South Korea.
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Edwardsiella tarda TraT is an anti-complement factor and a cellular infection promoter. Commun Biol 2022; 5:637. [PMID: 35768577 PMCID: PMC9243006 DOI: 10.1038/s42003-022-03587-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 06/15/2022] [Indexed: 12/04/2022] Open
Abstract
Edwardsiella tarda is a well-known bacterial pathogen with a broad range of host, including fish, amphibians, and mammals. One eminent virulence feature of E. tarda is its strong ability to resist the killing of host serum complement, but the involving mechanism is unclear. In this report, we identified E. tarda TraT as a key player in both complement resistance and cellular invasion. TraT, a surface-localized protein, bound and recruited complement factor H onto E. tarda, whereby inhibiting complement activation via the alternative pathway. TraT also interacted with host CD46 in a specific complement control protein domain-dependent manner, whereby facilitating the cellular infection and tissue dissemination of E. tarda. Thus, by acting as an anti-complement factor and a cellular infection promoter, TraT makes an important contribution to the complement evasion and systemic infection of E. tarda. These results add insights into the pathogen-host interaction mechanism during E. tarda infection. Edwardsiella tarda TraT promotes cellular infection and serves as an anti-complement factor, shedding light on the mechanisms of E. tarda’s strong evasion of killing by the host.
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8
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Liu X, Wang X, Sun B, Sun L. The Involvement of Thiamine Uptake in the Virulence of Edwardsiella piscicida. Pathogens 2022; 11:pathogens11040464. [PMID: 35456139 PMCID: PMC9026889 DOI: 10.3390/pathogens11040464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/11/2022] [Accepted: 04/11/2022] [Indexed: 11/16/2022] Open
Abstract
Edwardsiella piscicida is a pathogenic bacterium, which can infect a number of fish species and cause a disease termed edwardsiellosis, threatening global fish farming with high prevalence and mortality. Thiamine (Vitamin B1), functioning in the form of thiamine pyrophosphate (TPP), is essential for almost all organisms. Bacteria acquire TPP by biosynthesis or by transportation of exogenous thiamine. TPP availability has been associated with bacterial pathogenicity, but the underlying mechanisms remain to be discovered. The role of thiamine in the pathogenicity of E. piscicida is unknown. In this study, we characterized a thiamine transporter (TT) operon in E. piscicida. The deletion of the TT operon resulted in an intracellular TPP lacking situation, which led to attenuated overall pathogenicity, impaired abilities associated with motility and host cell adhesion, as well as decreased expression of certain flagellar and adhesion genes. Moreover, TPP starvation led to intracellular c-di-GMP reduction, and introducing into the TPP-suppressed mutant strain an exogenous diguanylate cyclase for c-di-GMP synthesis restored the virulence loss. Taken together, this work reveals the involvement of thiamine uptake in the virulence regulation of E. piscicida, with c-di-GMP implicated in the process. These finding could be employed to explore potential drug targets against E. piscicida.
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Affiliation(s)
- Xin Liu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, CAS Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; (X.L.); (X.W.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266003, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinhui Wang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, CAS Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; (X.L.); (X.W.)
| | - Boguang Sun
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, CAS Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; (X.L.); (X.W.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Correspondence: (B.S.); (L.S.)
| | - Li Sun
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Institute of Oceanology, CAS Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; (X.L.); (X.W.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao 266003, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (B.S.); (L.S.)
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Bothammal P, Ganesh M, Vigneshwaran V, Anbarasu K, Ponmurugan K, Al-Dhabi NA, Natarajaseenivasan K. Construction of Genomic Library and Screening of Edwardsiella tarda Immunogenic Proteins for Their Protective Efficacy Against Edwardsiellosis. Front Immunol 2021; 12:764662. [PMID: 34868012 PMCID: PMC8636194 DOI: 10.3389/fimmu.2021.764662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/11/2021] [Indexed: 11/16/2022] Open
Abstract
Edwardsiella tarda is a severe aquaculture pathogen that can infect many hosts including humans, animals, and fish. Timely diagnosis and treatment are crucial for the control of edwardsiellosis in the aqua industry. By using rabbit polyclonal antibody, an expression gene library of virulent Edwardsiella tarda strain ED-BDU 1 isolated in south India was constructed and screened. The identified immune expressive proteins were characterized, and the corresponding coding sequences were cloned, expressed, and the purified recombinant proteins were used as antigens. The identified immunoreactive proteins namely HflC, HflK, and YhcI were studied for their immune protective potential in vivo by challenge experiments. The protective efficacy of HflC, HflK, and YhcI showed that the clearance of Edwardsiella from the host with ~ 60% survivability. Further, the immunoreactive proteins induce a strong immune response upon infection and elicit the significant production of IL-10, IFN-γ, Th1, and Th2 mediated mRNA expression and were therefore effective in vaccine production for edwardsiellosis.
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Affiliation(s)
- Palanisamy Bothammal
- Medical Microbiology Laboratory, Department of Microbiology, Center for Excellence in Life Sciences, Bharathidasan University, Tiruchirappalli, India
| | - Mohan Ganesh
- Medical Microbiology Laboratory, Department of Microbiology, Center for Excellence in Life Sciences, Bharathidasan University, Tiruchirappalli, India
| | - Vellaisamy Vigneshwaran
- Medical Microbiology Laboratory, Department of Microbiology, Center for Excellence in Life Sciences, Bharathidasan University, Tiruchirappalli, India
| | - Kumarasamy Anbarasu
- Microbial Biotechnology Laboratory, Department of Marine Biotechnology, School of Marine Sciences, Bharathidasan University, Tiruchirappalli, India
| | - Karuppiah Ponmurugan
- Department of Botany & Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Naif Abdullah Al-Dhabi
- Department of Botany & Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Kalimuthusamy Natarajaseenivasan
- Medical Microbiology Laboratory, Department of Microbiology, Center for Excellence in Life Sciences, Bharathidasan University, Tiruchirappalli, India
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Kaszowska M, Górska S, Knirel Y, Kalinchuk N, Gamian A, Katzenellenbogen E. Structural analysis of Edwardsiella tarda PCM 1155 O-polysaccharide revealed the presence of unique β-L-RhapNAc3NAc derivative. Carbohydr Res 2021; 509:108423. [PMID: 34507179 DOI: 10.1016/j.carres.2021.108423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/18/2021] [Accepted: 08/18/2021] [Indexed: 10/20/2022]
Abstract
The chemical structure of the lipopolysaccharide O-polysaccharide repeating unit of Edwardsiella tarda strain PCM 1155 was studied for the first time. The complete structure of repeating unit was investigated by chemical methods, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, and matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The rarely occurring monosaccharide, 2,3-diacetamido-2,3,6-trideoxy-l-mannose (L-RhapNAc3NAc) was identified. The following structure was established.
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Affiliation(s)
- Marta Kaszowska
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, PL-53-114, Wroclaw, Poland.
| | - Sabina Górska
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, PL-53-114, Wroclaw, Poland.
| | - Yuriy Knirel
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Moscow, Russia
| | - Nadezhda Kalinchuk
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991, Moscow, Russia
| | - Andrzej Gamian
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, PL-53-114, Wroclaw, Poland
| | - Ewa Katzenellenbogen
- Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, PL-53-114, Wroclaw, Poland
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11
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Li XP, Zhang J. Tongue sole (Cynoglossus semilaevis) interleukin 10 receptors are involved in the immune response against bacterial infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 115:103885. [PMID: 33045275 DOI: 10.1016/j.dci.2020.103885] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 10/06/2020] [Accepted: 10/06/2020] [Indexed: 06/11/2023]
Abstract
Interleukin (IL)-10, an immune-regulatory cytokine, exerts various biological functions through interaction with IL-10 receptors. In teleost, very limited functional studies on IL-10 receptors have been documented. In this study, we reported the expression patterns of IL-10 receptor 1 (CsIL-10R1) and receptor 2 (CsIL-10R2) of tongue sole (Cynoglossus semilaevis) and examined their biological properties. The expression of CsIL-10R1 and CsIL-10R2 occurred in multiple tissues and were regulated by bacterial challenge. In vitro binding studies showed that recombinant extracellular region of CsIL-10R1 (rCsIL-10R1ex) rather than rCsIL-10R2ex could bind with rCsIL-10. Cellular study showed that both CsIL-10R1 and CsIL-10R2 were expressed on peripheral blood leukocytes (PBLs), and blockade of CsIL-10R1 or CsIL-10R2 by antibody could reduce inhibitory effect of CsIL-10 on ROS production of PBLs. When injected in vivo, anti-rCsIL-10R1 or anti-rCsIL-10R2 antibody dramatically promoted the expression of proinflammatory cytokines and suppressed bacterial dissemination in tongue sole tissues. Consistently, the overexpression of CsIL-10R1 or CsIL-10R2 significantly enhanced bacterial dissemination, and the overexpression of CsIL-10R1M bearing STAT3 site mutation reduced bacterial dissemination. Overall, these results demonstrate for the first time teleost IL-10 receptors play a negative role in antibacterial immunity and add insight into the function of CsIL-10 receptors.
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Affiliation(s)
- Xue-Peng Li
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; School of Ocean, Yantai University, Yantai, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Jian Zhang
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; School of Ocean, Yantai University, Yantai, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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12
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Li MF, Jia BB, Sun YY, Sun L. The Translocation and Assembly Module (TAM) of Edwardsiella tarda Is Essential for Stress Resistance and Host Infection. Front Microbiol 2020; 11:1743. [PMID: 32793174 PMCID: PMC7393178 DOI: 10.3389/fmicb.2020.01743] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 07/03/2020] [Indexed: 11/28/2022] Open
Abstract
Translocation and assembly module (TAM) is a protein channel known to mediate the secretion of virulence factors during pathogen infection. Edwardsiella tarda is a Gram-negative bacterium that is pathogenic to a wide range of farmed fish and other hosts including humans. In this study, we examined the function of the two components of the TAM, TamA and TamB, of E. tarda (named tamAEt and tamBEt, respectively). TamAEt was found to localize on the surface of E. tarda and be recognizable by TamAEt antibody. Compared to the wild type, the tamA and tamB knockouts, TX01ΔtamA and TX01ΔtamB, respectively, were significantly reduced in motility, flagella formation, invasion into host cells, intracellular replication, dissemination in host tissues, and inducing host mortality. The lost virulence capacities of TX01ΔtamA and TX01ΔtamB were restored by complementation with the tamAEt and tamBEt genes, respectively. Furthermore, TX01ΔtamA and TX01ΔtamB were significantly impaired in the ability to survive under low pH and oxidizing conditions, and were unable to maintain their internal pH balance and cellular structures in acidic environments, which led to increased susceptibility to lysozyme destruction. Taken together, these results indicate that TamAEt and TamBEt are essential for the virulence of E. tarda and required for E. tarda to survive under stress conditions.
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Affiliation(s)
- Mo-Fei Li
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Bei-Bei Jia
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yuan-Yuan Sun
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Li Sun
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
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13
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Wang Y, Miao Y, Hu LP, Kai W, Zhu R. Immunization of mice against alpha, beta, and epsilon toxins of Clostridium perfringens using recombinant rCpa-b-x expressed by Bacillus subtilis. Mol Immunol 2020; 123:88-96. [PMID: 32447084 DOI: 10.1016/j.molimm.2020.05.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 03/30/2020] [Accepted: 05/06/2020] [Indexed: 12/15/2022]
Abstract
The anaerobic pathogen Clostridium perfringens is the most potent cause of intestinal diseases, such as enterotoxemia, hemorrhagic enteritis, and lamb dysentery, in sheep. Three toxinotypes (B, C, and D) are usually the cause of these diseases and are mainly mediated via three important exotoxins: alpha toxin (CPA), beta toxin (CPB), and epsilon toxin (ETX). We have designed a chimeric protein, rCpa-b-x, that contains the C-terminal binding region of CPA, partial sequence of CPB, and ETX (Cpa247-370, Cpb108-305, and EtxH118P, respectively) according to the principle of structural vaccinology. The rCpa-b-x protein was then expressed by pHT43 plasmid in vivo using Bacillus subtilis as a delivery vector (Bs-pHT43-Cpa-b-x). The immunological activity of the rCpa-b-x protein was verified by western blot and its immunological efficacy was evaluated in a murine model. Oral administration with a recombinant agent caused local mucosal and systemic immune responses, and serum lgG and intestinal mucosal secretory IgA (sIgA) antibody titers were significantly increased. Levels of IL-2, IL-4, and IFN-γ were significantly higher in lymphocytes isolated from the Bs-pHT43-Cpa-b-x group compared with levels from the control groups. The percentages of CD4+ and CD8+ T lymphocytes in the Bs-pHT43-Cpa-b-x and inactivated vaccine (IV) groups were in the normal range. Mice of vaccine groups and control groups were challenged with 1x LD100 unit filtrate containing alpha, beta, and epsilon toxins. Mice in the Bs-pHT43-Cpa-b-x group were found to have lower rates of morbidity. The active immunization of mice with Bs-pHT43-Cpa-b-x still maintained 85% to 90% survival at the end of the 10-day observation period, whereas mice of control groups died within two to five days. The results of this study demonstrate the effectiveness of Bs-pHT43-Cpa-b-x in preventing C. perfringens infection in mice, and that Bs-pHT43-Cpa-b-x could be considered a potential vaccine against C. perfringens.
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Affiliation(s)
- Yujian Wang
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271000, China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Taian 271000, China
| | - Yongqiang Miao
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271000, China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Taian 271000, China
| | - Li-Ping Hu
- Animal Disease Prevention and Control Center of Shandong Province, Animal Husbandry and Veterinary Bureau of Shandong Province, Jinan, China
| | - Wei Kai
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271000, China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Taian 271000, China.
| | - Ruiliang Zhu
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Taian 271000, China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, Taian 271000, China.
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14
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Sun Y, Ding S, He M, Liu A, Long H, Guo W, Cao Z, Xie Z, Zhou Y. Construction and analysis of the immune effect of Vibrio harveyi subunit vaccine and DNA vaccine encoding TssJ antigen. FISH & SHELLFISH IMMUNOLOGY 2020; 98:45-51. [PMID: 31887410 DOI: 10.1016/j.fsi.2019.12.079] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/24/2019] [Accepted: 12/26/2019] [Indexed: 06/10/2023]
Abstract
Vibrio harveyi, a severe pathogen infects different kinds of sea animals, causes huge economic loss in aquaculture industry. In order to control the Vibriosis disease caused mainly by V. harveyi and other Vibrio spp., the best solution lies in developing corresponding efficient vaccines. In this study, we have cloned and analysed a putative antigen TssJ from the T6SS of V. harveyi, which has the potential as a vaccine against infection. The sequence analysis and western blotting experiments indicated that TssJ anchored in outer membrane and there were several antigenic determinants existed on its extracellular region. Two forms of universal vaccines, subunit vaccine and DNA vaccine, were developed based on TssJ and applied in Trachinotus ovatus. The results showed that both of the two vaccines could generate a moderate protection in fish against V. harveyi. The relative percentage survival (RPS) of subunit vaccine and DNA vaccine were 52.39% and 69.11%, respectively. Immunological analysis showed both subunit vaccine and DNA vaccine enhanced acid phosphatase, alkaline phosphatase, superoxide dismutase, and lysozyme activities. Specific serum antibodies against TssJ in the fish vaccinated with subunit vaccine was much higher than that in the DNA vaccine group. Several immune-related genes, i.e., IL10, C3, MHC Iα, MHC IIα, and IgM, were induced both by the two forms of vaccines. TNFα and Mx were only upregulated in the DNA vaccine group. However, the induction levels of these genes induced by DNA vaccine were higher than subunit vaccine. All these findings suggested that TssJ from V. harveyi had a potential application value in vaccine industry.
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Affiliation(s)
- Yun Sun
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China
| | - Susu Ding
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China
| | - Mingwang He
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China
| | - Anzhu Liu
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China
| | - Hao Long
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China
| | - Weiliang Guo
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China
| | - Zhenjie Cao
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China
| | - Zhenyu Xie
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China.
| | - Yongcan Zhou
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, PR China.
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15
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Jia BB, Jin CD, Li MF. The trypsin-like serine protease domain of Paralichthys olivaceus complement factor I regulates complement activation and inhibits bacterial growth. FISH & SHELLFISH IMMUNOLOGY 2020; 97:18-26. [PMID: 31830570 DOI: 10.1016/j.fsi.2019.12.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/07/2019] [Accepted: 12/09/2019] [Indexed: 06/10/2023]
Abstract
In mammals, complement factor I (CFI) is a serine protease in serum and plays a pivotal role in the regulation of complement activation. In the presence of cofactor, CFI cleaves C3b to iC3b, and further degrades iC3b to C3c and C3d. In teleost, the function of CFI is poorly understood. In this study, we examined the immunological property of CFI from Japanese flounder (Paralichthys olivaceus) (PoCFI), a teleost species with important economic value. PoCFI is composed of 597 amino acid residues and possesses a trypsin-like serine protease (Tryp) domain. We found that PoCFI expressions occurred in nine different tissues and were upregulated by bacterial challenge. Recombinant PoCFI-Tryp (rPoCFI-Tryp) inhibited complement activation and degraded C3b in serum. rPoCFI-Tryp exhibited apparent binding capacities to a board-spectrum of bacteria and inhibited bacterial growth. These results provide the first evidence to indicate that CFI in teleost negatively regulates complement activation via degradation C3b, and probably plays a role in host immune defense against bacterial infection.
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Affiliation(s)
- Bei-Bei Jia
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology Qingdao, China; University of Chinese Academy of Sciences, Beijing, China
| | - Cheng-Dong Jin
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology Qingdao, China; University of Chinese Academy of Sciences, Beijing, China
| | - Mo-Fei Li
- CAS Key Laboratory of Experimental Marine Biology, CAS Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology Qingdao, China.
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16
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Xue D, Guang-Hua W, Yan-Li S, Min Z, Yong-Hua H. Black rockfish C-type lectin, SsCTL4: A pattern recognition receptor that promotes bactericidal activity and virus escape from host immune defense. FISH & SHELLFISH IMMUNOLOGY 2018; 79:340-350. [PMID: 29803666 DOI: 10.1016/j.fsi.2018.05.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/16/2018] [Accepted: 05/17/2018] [Indexed: 06/08/2023]
Abstract
C-type lectin (CTL) is an immune receptor and is received extensive attention of its important roles in immune response and immune escape. Some CTL, such as CTL4, has been well characterized in human and several other mammals, but much less documentation exists about the immunological function of CTL4 in lower vertebrates. In the present study, a C-type lectin domain family 4 member, SsCTL4, which is also high homology with CD209 antigen-like protein, from the teleost fish black rockfish (Sebastes schlegelii) was identified and examined at expression and functional levels. The open reading frame of SsCTL4 is 765 bp, and the deduced amino acid sequence of SsCTL4 shares 78%-84% overall identities with the C-type lectin of several fish species. In silico analysis identified several conserved C-type lectin features, including a carbohydrate-recognition domain and four disulfide bond-forming cysteine residues. Expression of SsCTL4 occurred in multiple tissues and was upregulated during bacterial and viral infection. Recombinant SsCTL4 (rSsCTL4) exhibited apparent binding activities against bacteria (Edwardsiella tarda and Vibrio anguillarum) and virus (infectious spleen and kidney necrosis virus, ISKNV). rSsCTL4 was able to agglutinate the Gram-negative and Gram-positive bacteria in a Ca2+-dependent manner. The agglutinating ability of rSsCTL4 was abolished in the absence of calcium or presence of mannose. rSsCTL4 also increased macrophage bactericidal activity. In the presence of rSsCTL4, fish exhibited enhanced resistance against bacterial infection but increased susceptibility to viral infections. Collectively, these results indicate that SsCTL4 serves as a pattern recognition receptor that not only promotes bactericidal activity, but may also serve as targets for virus manipulation of host defense system.
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Affiliation(s)
- Du Xue
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Wang Guang-Hua
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Su Yan-Li
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China
| | - Zhang Min
- Marine Science and Engineering College, Qingdao Agricultural University, Qingdao, 266109, China.
| | - Hu Yong-Hua
- Institute of Tropical Biosciece and Biotechnology, Key Laboratory of Biology and Genetic Resources of Tropical Crops of Ministry of Agriculture, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Haikou, 571101, China.
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17
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Galactose-1-phosphate uridyltransferase (GalT), an in vivo-induced antigen of Actinobacillus pleuropneumoniae serovar 5b strain L20, provided immunoprotection against serovar 1 strain MS71. PLoS One 2018; 13:e0198207. [PMID: 29856812 PMCID: PMC5983418 DOI: 10.1371/journal.pone.0198207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 05/15/2018] [Indexed: 11/19/2022] Open
Abstract
GALT is an important antigen of Actinobacillus pleuropneumoniae (APP), which was shown to provide partial protection against APP infection in a previous study in our lab. The main purpose of the present study is to investigate GALT induced cross-protection between different APP serotypes and elucidate key mechanisms of the immune response to GALT antigenic stimulation. Bioinformatic analysis demonstrated that galT is a highly conserved gene in APP, widely distributed across multiple pathogenic strains. Homologies between any two strains ranges from 78.9% to 100% regarding the galT locus. Indirect enzyme-linked immunosorbent assay (ELISA) confirmed that GALT specific antibodies could not be induced by inactivated APP L20 or MS71 whole cell bacterin preparations. A recombinant fusion GALT protein derived from APP L20, however has proven to be an effective cross-protective antigen against APP sevorar 1 MS71 (50%, 4/8) and APP sevorar 5b L20 (75%, 6/8). Histopathological examinations have confirmed that recombinant GALT vaccinated animals showed less severe pathological signs in lung tissues than negative controls after APP challenge. Immunohistochemical (IHC) analysis indicated that the infiltration of neutrophils in the negative group is significantly increased compared with that in the normal control (P<0.001) and that in surviving animals is decreased compared to the negative group. Anti-GALT antibodies were shown to mediate phagocytosis of neutrophils. After interaction with anti-GALT antibodies, survival rate of APP challenged vaccinated animals was significantly reduced (P<0.001). This study demonstrated that GALT is an effective cross-protective antigen, which could be used as a potential vaccine candidate against multiple APP serotypes.
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18
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Li MF, Sun L. Edwardsiella tarda Sip2: A Serum-Induced Protein That Is Essential to Serum Survival, Acid Resistance, Intracellular Replication, and Host Infection. Front Microbiol 2018; 9:1084. [PMID: 29887847 PMCID: PMC5980991 DOI: 10.3389/fmicb.2018.01084] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 05/07/2018] [Indexed: 12/12/2022] Open
Abstract
Edwardsiella tarda is a broad-host pathogen that can infect mammals, reptiles, and fish. E. tarda exhibits a remarkable ability to survive in host serum and replicate in host phagocytes, but the underlining mechanism is unclear. In this study, in order to identify E. tarda proteins involved in serum resistance, iTRAQ proteomic analysis was performed to examine the whole-cell protein profiles of TX01, a pathogenic E. tarda isolate, in response to serum treatment. Of the differentially expressed proteins identified, one (named Sip2) possesses a conserved hydrogenase domain and is homologous to the putative hydrogenase accessory protein HypB. When Sip2 was expressed in Escherichia coli, it significantly enhanced the survival of the host cells in serum. Compared to TX01, the sip2 knockout, TX01Δsip2, was dramatically reduced in the ability of hydrogenase activity, serum resistance, intracellular replication, dissemination in fish tissues, and causing mortality in infected fish. The lost virulence capacities of TX01Δsip2 were restored by complementation with the sip2 gene. Furthermore, TX01Δsip2 was significantly reduced in the capacity to grow under low pHs and iron-depleted conditions, and was unable to maintain its internal pH in acidic environment. Taken together, these results indicate that Sip2 is a novel serum-induced protein that is essential to serum resistance, cellular and tissue infection, and coping with acidic stress via its ability to modulate intracellular pH.
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Affiliation(s)
- Mo-fei Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Li Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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19
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Li MF, Sun L. Characterization of a teleost membrane-associated protein that is involved in the regulation of complement activation and bacterial infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 79:142-149. [PMID: 29066398 DOI: 10.1016/j.dci.2017.10.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 10/18/2017] [Accepted: 10/18/2017] [Indexed: 06/07/2023]
Abstract
In mammals, membrane-associated complement regulatory proteins (MCRP) can protect host cells from the damaging of the activated complement. In teleost, few studies on the function of MCRP have been documented. In the present report, we identified a MCRP (named CsMCRP) from the teleost fish tongue sole Cynoglossus semilaevis and examined its immune function. CsMCRP shares moderate sequence identities with fish DAF-like molecules. CsMCRP was predicted to be a transmembrane protein with three short consensus repeats located in the extracellular region. CsMCRP expression occurred in nine different tissues, especially blood, and in peripheral blood leukocytes (PBL). Recombinant CsMCRP inhibited complement activation and interacted with bacterial pathogen, the latter in a highly selective manner. Antibody blocking the CsMCRP on PBL significantly inhibited bacterial infection of PBL. These results indicate that teleost CsMCRP is both a regulator of complement activation and a cellular receptor involved in bacterial invasion.
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Affiliation(s)
- Mo-Fei Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Li Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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20
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A teleost CD46 is involved in the regulation of complement activation and pathogen infection. Sci Rep 2017; 7:15028. [PMID: 29101395 PMCID: PMC5670209 DOI: 10.1038/s41598-017-15124-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 10/23/2017] [Indexed: 01/12/2023] Open
Abstract
In mammals, CD46 is involved in the inactivation of complement by factor I (FI). In teleost, study on the function of CD46 is very limited. In this study, we examined the immunological property of a CD46 molecule (CsCD46) from tongue sole, a teleost species with important economic value. We found that recombinant CsCD46 (rCsCD46) interacted with FI and inhibited complement activation in an FI-dependent manner. rCsCD46 also interacted with bacterial pathogens via a different mechanism to that responsible for the FI interaction, involving different rCsCD46 sites. Cellular study showed that CsCD46 was expressed on peripheral blood leukocytes (PBL) and protected the cells against the killing effect of complement. When the CsCD46 on PBL was blocked by antibody before incubation of the cells with bacterial pathogens, cellular infection was significantly reduced. Consistently, when tongue sole were infected with bacterial pathogens in the presence of rCsCD46, tissue dissemination and survival of the pathogens were significantly inhibited. These results provide the first evidence to indicate that CD46 in teleosts negatively regulates complement activation via FI and protects host cells from complement-induced damage, and that CD46 is required for optimal bacterial infection probably by serving as a receptor for the bacteria.
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21
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Núñez-Díaz JA, Fumanal M, Viguera E, Moriñigo MA, Balebona MC. Use of in vivo induced technology to identify antigens expressed by Photobacterium damselae subsp. piscicida during infection of Senegalese sole (Solea senegalensis). FISH & SHELLFISH IMMUNOLOGY 2017; 64:446-456. [PMID: 28359946 DOI: 10.1016/j.fsi.2017.03.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/22/2017] [Accepted: 03/26/2017] [Indexed: 06/07/2023]
Abstract
Photobacterium damselae subsp. piscicida (Phdp), the causative agent of photobacteriosis, is an important pathogen in marine aquaculture that affects many different fish species worldwide, including Solea senegalensis, an important fish species for aquaculture in the south of Europe. Bacteria express different repertoires of proteins in response to environmental conditions and when invading a host, sense in vivo environment and adapt by changing the expression of specific proteins. In the case of pathogens, identification of genes with up-regulated expression in vivo compared to in vitro conditions might give an insight into the genes relevant to the bacterial virulence. In the present work, in vivo induced antigen technology (IVIAT) has been used to search for Phdp genes only expressed or up-regulated in infected S. senegalensis. An expression library from Phdp was assayed against pooled sera from convalescent S. senegalensis specimens and 18 clones were positive, indicating that proteins encoded are expressed by Phdp during S. senegalensis infection and are immunogenic for this fish species. In addition, five proteins were reactive against adsorbed sera, indicating their in vivo induced character. Inosine-5'-monophosphate dehydrogenase, serine hydroxy methyltransferase and alanyl-tRNA synthethase, involved in aminoacid and nucleotide metabolism, the protein with antioxidant activity alkyl hydroperoxide reductase and a non-ribosomal peptide synthetase responsible for the synthesis of the siderophore piscibactin have been identified as antigens induced in Phdp during S. senegalensis infection. Proteins induced during in vivo growth of Phdp represent promising targets for the development of novel antimicrobial or prophylactic agents in the treatment and prevention of photobacteriosis.
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Affiliation(s)
- J A Núñez-Díaz
- Universidad de Málaga, Departamento de Microbiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - M Fumanal
- Universidad de Málaga, Departamento de Microbiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - E Viguera
- Universidad de Málaga, Área de Genética, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - M A Moriñigo
- Universidad de Málaga, Departamento de Microbiología, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - M C Balebona
- Universidad de Málaga, Departamento de Microbiología, Campus de Teatinos s/n, 29071 Málaga, Spain.
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22
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Sun Y, Zhang J, Qin L, Yan C, Zhang X, Liu D. Identification and validation of sRNAs in Edwardsiella tarda S08. PLoS One 2017; 12:e0172783. [PMID: 28267754 PMCID: PMC5340389 DOI: 10.1371/journal.pone.0172783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 02/09/2017] [Indexed: 11/29/2022] Open
Abstract
Bacterial small non-coding RNAs (sRNAs) are known as novel regulators involved in virulence, stress responsibility, and so on. Recently, a lot of new researches have highlighted the critical roles of sRNAs in fine-tune gene regulation in both prokaryotes and eukaryotes. Edwardsiella tarda (E. tarda) is a gram-negative, intracellular pathogen that causes edwardsiellosis in fish. Thus far, no sRNA has been reported in E. tarda. The present study represents the first attempt to identify sRNAs in E. tarda S08. Ten sRNAs were validated by RNA sequencing and quantitative PCR (qPCR). ET_sRNA_1 and ET_sRNA_2 were homolous to tmRNA and GcvB, respectively. However, the other candidate sRNAs have not been reported till now. The cellular abundance of 10 validated sRNA was detected by qPCR at different growth phases to monitor their biosynthesis. Nine candidate sRNAs were expressed in the late-stage of exponential growth and stationary stages of growth (36~60 h). And the expression of the nine sRNAs was growth phase-dependent. But ET_sRNA_10 was almost expressed all the time and reached the highest peak at 48 h. Their targets were predicted by TargetRNA2 and each sRNA target contains some genes that directly or indirectly relate to virulence. These results preliminary showed that sRNAs probably play a regulatory role of virulence in E. tarda.
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Affiliation(s)
- Yuying Sun
- College of Marine Life and Fisheries, Huaihai Institute of Technology, Lianyungang, China
- Jiangsu Marine Resources Development Research Institute, Lianyungang, China
- Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Huaihai Institute of Technology, Lianyungang, China
| | - Jiquan Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- * E-mail:
| | - Lei Qin
- College of Marine Life and Fisheries, Huaihai Institute of Technology, Lianyungang, China
| | - Cui Yan
- College of Marine Life and Fisheries, Huaihai Institute of Technology, Lianyungang, China
| | - Xiaojun Zhang
- College of Marine Life and Fisheries, Huaihai Institute of Technology, Lianyungang, China
| | - Dandan Liu
- College of Marine Life and Fisheries, Huaihai Institute of Technology, Lianyungang, China
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Li MF, Li J, Sun L. CsMAP34, a teleost MAP with dual role: A promoter of MASP-assisted complement activation and a regulator of immune cell activity. Sci Rep 2016; 6:39287. [PMID: 28008939 PMCID: PMC5180248 DOI: 10.1038/srep39287] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 11/22/2016] [Indexed: 01/28/2023] Open
Abstract
In teleost fish, the immune functions of mannan-binding lectin (MBL) associated protein (MAP) and MBL associated serine protease (MASP) are scarcely investigated. In the present study, we examined the biological properties both MAP (CsMAP34) and MASP (CsMASP1) molecules from tongue sole (Cynoglossus semilaevis). We found that CsMAP34 and CsMASP1 expressions occurred in nine different tissues and were upregulated by bacterial challenge. CsMAP34 protein was detected in blood, especially during bacterial infection. Recombinant CsMAP34 (rCsMAP34) bound C. semilaevis MBL (rCsBML) when the latter was activated by bacteria, while recombinant CsMASP1 (rCsMASP1) bound activated rCsBML only in the presence of rCsMAP34. rCsMAP34 stimulated the hemolytic and bactericidal activities of serum complement, whereas anti-CsMAP34 antibody blocked complement activities. Knockdown of CsMASP1 in C. semilaevis resulted in significant inhibition of complement activities. Furthermore, rCsMAP34 interacted directly with peripheral blood leukocytes (PBL) and enhanced the respiratory burst, acid phosphatase activity, chemotactic activity, and gene expression of PBL. These results indicate for the first time that a teleost MAP acts one hand as a regulator that promotes the lectin pathway of complement activation via its ability to recruit MBL to MASP, and other hand as a modulator of immune cell activity.
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Affiliation(s)
- Mo-Fei Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Jun Li
- School of Biological Sciences, Lake Superior State University, Sault Ste Marie, MI, USA
| | - Li Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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Li MF, Zhang J. CsTNF1, a teleost tumor necrosis factor that promotes antibacterial and antiviral immune defense in a manner that depends on the conserved receptor binding site. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 55:65-75. [PMID: 26478190 DOI: 10.1016/j.dci.2015.10.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 10/12/2015] [Accepted: 10/12/2015] [Indexed: 06/05/2023]
Abstract
Tumor necrosis factor (TNF) is one of the most important cytokines involved in inflammation, apoptosis, cell proliferation, and stimulation of the immune system. The TNF gene has been cloned in teleost fish; however, the in vivo function of fish TNF is essentially unknown. In this study, we report the identification of a TNF homologue, CsTNF1, from tongue sole (Cynoglossus semilaevis) and analysis of its expression and biological effect. CsTNF1 is composed of 242 amino acid residues and possesses a TNF domain and conserved receptor binding sites. Expression of CsTNF1 was detected in a wide range of tissues and up-regulated in a time-dependent manner by experimental challenge with bacterial and viral pathogens. Bacterial infection of peripheral blood leukocytes (PBL) caused extracellular secretion of CsTNF1. Purified recombinant CsTNF1 (rCsTNF1) was able to bind to PBL and stimulate the respiratory burst activity of PBL. In contrast, rCsTNF1M1 and rCsTNF1M2, the mutant CsTNF1 bearing substitutions at the receptor binding site, failed to activate PBL. Fish administered with rCsTNF1, but not with rCsTNF1M1 and rCsTNF1M2, exhibited enhanced expression of IL-1, IL-6, IL-8, IL-27, TLR9 and G3BP in a time-dependent manner and augmented resistance against bacterial and viral infection. These results provide the first evidence that the receptor binding sites are essential to a fish TNF, and that CsTNF1 is involved in the innate immune defense of fish against microbial pathogens.
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Affiliation(s)
- Mo-fei Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jian Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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Zhang J, Zhang M, Sun L. Junctional adhesion molecule A of red drum (Sciaenops ocellatus): a possible immunomodulator and a target for bacterial immune evasion. Vet Immunol Immunopathol 2014; 161:99-107. [PMID: 25108665 DOI: 10.1016/j.vetimm.2014.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 07/18/2014] [Indexed: 12/01/2022]
Abstract
Junctional adhesion molecules (JAMs) are a family of type I cell surface receptors with two immunoglobulin (Ig) domains in the extracellular region. The family contains three classical members, i.e., JAM-A, -B, and -C. To date very little is known about the function of JAMs in teleost. In this work, we identified a JAM-A homologue (named SoJAMa) from red drum (Sciaenops ocellatus) and examined its expression and biological property. SoJAMa is composed of 347 amino acid residues and was predicted to be a transmembrane protein with a large extracellular region that contains two Ig domains. SoJAMa expression occurred in multiple tissues, in particular immune relevant organs. SoJAMa expression was downregulated by experimental challenge with an extracellular pathogen but upregulated by challenge with an intracellular pathogen that is known to be capable of immune evasion. Likewise, cellular study showed that infection of peripheral blood leukocytes (PBL) with intracellular pathogen induced significantly higher expression of SoJAMa. Immunofluorescence microscopy showed that SoJAMa was localized on the surface of PBL and recognized by antibodies against recombinant SoJAMa. Blockage of the SoJAMa on PBL with antibodies resulted in augmented respiratory burst activity. Consistently, antibody-treated PBL exhibited enhanced resistance against bacterial infection. Taken together, these results suggest for the first time that a teleost JAM-A likely possesses immunoregulatory property in a negative manner, and that this property may be taken advantage of by intracellular pathogens as an invasion strategy.
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Affiliation(s)
- Jian Zhang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Min Zhang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; College of Marine Science and Engineering, Qingdao Agricultural University, Chengyang, Qingdao 266109, China
| | - Li Sun
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
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Zhang BC, Zhang J, Xiao ZZ, Sun L. Rock bream (Oplegnathus fasciatus) viperin is a virus-responsive protein that modulates innate immunity and promotes resistance against megalocytivirus infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 45:35-42. [PMID: 24525178 DOI: 10.1016/j.dci.2014.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 02/03/2014] [Accepted: 02/04/2014] [Indexed: 06/03/2023]
Abstract
Viperin in mammals is known to be an antiviral protein that inhibits the replication of diverse DNA and RNA viruses. In teleost, viperin homologues have been identified in a large number of species and, in some cases, are stimulated in transcription by viruses. However, the biological significance of fish viperin protein in antiviral immunity has not been investigated. In this study, we identified a viperin homologue from rock bream (Oplegnathus fasciatus) (named OfVip) and examined its expression pattern, subcellular localization, and immune effect. We found that OfVip expression occurred in eight tissues, and experimental challenge of rock bream with the viral fish pathogen megalocytivirus upregulated OfVip expression in kidney, liver, and spleen. OfVip was localized in the endoplasmic reticulum under normal physiological conditions, and viral infection induced subcellular redistribution of OfVip. Transient transfection of cultured fish cells with an OfVip-expressing plasmid caused enhanced cellular resistance against megalocytivirus challenge. Consistently, in vivo study showed that rock bream overexpressing OfVip exhibited significantly reduced viral loads in tissues following experimental infection with megalocytivirus. Furthermore, OfVip upregulated the expression of a wide range of immune genes, including those that are known to participate in antiviral immunity. Taken together, these results indicate for the first time that a teleost viperin is a virus-responsive protein that is modulated in subcellular localization by viral infection, and that viperin regulates the immune reactions of the host fish in a manner that augments resistance against viral infection.
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Affiliation(s)
- Bao-cun Zhang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Zhang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Zhi-zhong Xiao
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Li Sun
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
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27
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Li MF, Zhang BC, Li J, Sun L. Sil: a Streptococcus iniae bacteriocin with dual role as an antimicrobial and an immunomodulator that inhibits innate immune response and promotes S. iniae infection. PLoS One 2014; 9:e96222. [PMID: 24781647 PMCID: PMC4004548 DOI: 10.1371/journal.pone.0096222] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 04/04/2014] [Indexed: 11/18/2022] Open
Abstract
Streptococcus iniae is a Gram-positive bacterium and a severe pathogen to a wide range of economically important fish species. In addition, S. iniae is also a zoonotic pathogen and can cause serious infections in humans. In this study, we identified from a pathogenic S. iniae strain a putative bacteriocin, Sil, and examined its biological activity. Sil is composed of 101 amino acid residues and shares 35.6% overall sequence identity with the lactococcin 972 of Lactococcus lactis. Immunoblot analysis showed that Sil was secreted by S. iniae into the extracellular milieu. Purified recombinant Sil (rSil) exhibited a dose-dependent inhibitory effect on the growth of Bacillus subtilis but had no impact on the growths of other 16 Gram-positive bacteria and 10 Gram-negative bacteria representing 23 different bacterial species. Treatment of rSil by heating at 50°C abolished the activity of rSil. rSil bound to the surface of B. subtilis but induced no killing of the target cells. Cellular study revealed that rSil interacted with turbot (Scophthalmus maximus) head kidney monocytes and inhibited the innate immune response of the cells, which led to enhanced cellular infection of S. iniae. Antibody blocking of the extracellular Sil produced by S. iniae significantly attenuated the infectivity of S. iniae. Consistent with these in vitro observations, in vivo study showed that administration of turbot with rSil prior to S. iniae infection significantly increased bacterial dissemination and colonization in fish tissues. Taken together, these results indicate that Sil is a novel virulence-associated bacteriostatic and an immunoregulator that promotes S. iniae infection by impairing the immune defense of host fish.
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Affiliation(s)
- Mo-fei Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bao-cun Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jun Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- School of Biological Sciences, Lake Superior State University, Sault Ste Marie, Michigan, United States of America
| | - Li Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Collaborative Innovation Center of Deep Sea Biology, Zhejiang University, Hangzhou, China
- * E-mail:
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Hu YH, Li YX, Sun L. Edwardsiella tarda Hfq: impact on host infection and global protein expression. Vet Res 2014; 45:23. [PMID: 24568370 PMCID: PMC4015145 DOI: 10.1186/1297-9716-45-23] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 02/13/2014] [Indexed: 12/29/2022] Open
Abstract
Hfq is an RNA-binding protein that plays an important role in many cellular processes. In this study, we examined the biological effect of the Hfq of Edwardsiella tarda, a severe fish pathogen with a broad host range that includes humans. To facilitate the study, a markerless hfq in-frame deletion wild type, TXhfq, was constructed. Compared to the wild type TX01, TXhfq exhibited (i) retarded planktonic and biofilm growth, (ii) decreased resistance against oxidative stress, (iii) attenuated overall virulence and tissue dissemination and colonization capacity, (iv) impaired ability to replicate in host macrophages and to block host immune response. Introduction of a trans-expressed hfq gene into TXhfq restored the lost virulence of TXhfq. To identify potential Hfq targets, comparative global proteomic analysis was conducted, which revealed that 20 proteins belonging to different functional categories were differentially expressed in TXhfq and TX01. Quantitative real time RT-PCR analysis showed that the mRNA levels of two thirds of the genes of the identified proteins were consistent with the proteomic results. Since TXhfq is dramatically attenuated in virulence, we further examined its potential as a naturally delivered vaccine administered via the immersion route in a flounder model. The results showed that TXhfq induced effective protection against lethal E. tarda challenge. Taken together, our study indicated that Hfq is required for the normal operation of E. tarda in multiple aspects, and that Hfq probably exerts a regulatory effect on a wide range of target genes at both transcription and post-transcription levels.
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Affiliation(s)
| | | | - Li Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
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29
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Li MF, Sun BG, Xiao ZZ, Sun L. First characterization of a teleost Epstein-Barr virus-induced gene 3 (EBI3) reveals a regulatory effect of EBI3 on the innate immune response of peripheral blood leukocytes. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 41:514-522. [PMID: 23932982 DOI: 10.1016/j.dci.2013.07.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 07/30/2013] [Accepted: 07/30/2013] [Indexed: 05/29/2023]
Abstract
Epstein-Barr virus-induced gene 3 (EBI3) encodes a protein that in mammals is known to be a subunit of interleukin (IL)-27 and IL-35, both which regulate cytokine production and inflammatory response. To date, no studies on fish EBI3 have been documented. In this work, we report the identification of an EBI3 homologue, CsEBI3, from tongue sole (Cynoglossus semilaevis) and analysis of its expression and biological effect. CsEBI3 is composed of 245 amino acid residues and possesses a Fibronectin type 3 (FN3) domain that is preserved in lower and higher vertebrates. Expression of CsEBI3 was detected in a wide range of tissues, in particular those of immune relevant organs, and upregulated in a time-dependent manner by experimental challenge with bacterial and viral pathogens. Bacterial infection of peripheral blood leukocytes (PBL) enhanced CsEBI3 expression and caused extracellular secretion of CsEBI3. Purified recombinant CsEBI3 (rCsEBI3) stimulated the respiratory burst activity of PBL and upregulated the expression of IL-1β, IL-8, Myd88, interferon-induced gene 15, CD28, and chemokines. In contrast, rCsEBI3M, a mutant CsEBI3 that lacks the FN3 domain failed to activate PBL and induced much weaker expression of the immune genes. Treatment of PBL with rCsEBI3, but not with the mutant rCsEBI3M, enhanced cellular resistance against bacterial invasion, whereas antibody blocking of CsEBI3 on PBL significantly reduced cellular resistance against bacterial infection. Taken together, these results indicate for the first time that a teleost EBI3 possesses immunoregulatory property in a manner that is dependent on the conserved FN3 domain, and that CsEBI3 is involved in the innate immune defense of PBL against microbial pathogens.
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Affiliation(s)
- Mo-fei Li
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, China
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30
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Song M, Xie J, Peng X, Li H. Identification of protective immunogens from extracellular secretome of Edwardsiella tarda. FISH & SHELLFISH IMMUNOLOGY 2013; 35:1932-1936. [PMID: 24099803 DOI: 10.1016/j.fsi.2013.09.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 09/22/2013] [Accepted: 09/25/2013] [Indexed: 06/02/2023]
Abstract
Edwardsiella tarda is an opportunistic pathogen that causes a great loss in aquaculture. Identification of immune protective immunogens is a key step for development of subunit vaccines and control of the infectious diseases caused by the bacterium. This study aims to identify the protective antigens from extracellular secretory proteome of E. tarda. Out of 38 extracellular secretory proteins predicted by PSORTb, 20 genes were randomly cloned and their recombinant proteins were expressed in Escherichia coli BL21 and purified by either affinity chromatography or inclusion body washing. The purified recombinant proteins were used for investigation of immune protection in zebrafish model using active immunization approach. Half of them had significant immune protection compared with the control. Out of them, four, EseC, ETAE_2088, FlgD and ETAE_2130, showed approximately 60% relative percent survivals as a result of the highly protective antigens identified. Except for FlgD, the other three were first reported here. Moreover, the present study identified EseC and ETAE_2088 in bacterial extracellular fraction. These results indicate that secretory proteome is an interesting pool used for identification of immune protective antigens, and the four highly protective antigens identified provide useful candidates for development of subunit vaccines.
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Affiliation(s)
- Ming Song
- Center for Proteomics and Metabolomics, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, MOE Key Lab Aquat Food Safety, Guangzhou 510275, People's Republic of China
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Wang C, Hu YH, Sun BG, Li J, Sun L. Edwardsiella tarda Ivy, a lysozyme inhibitor that blocks the lytic effect of lysozyme and facilitates host infection in a manner that is dependent on the conserved cysteine residue. Infect Immun 2013; 81:3527-33. [PMID: 23817616 PMCID: PMC3811778 DOI: 10.1128/iai.00503-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 06/22/2013] [Indexed: 02/04/2023] Open
Abstract
Edwardsiella tarda is a Gram-negative bacterial pathogen with a broad host range that includes fish and humans. In this study, we examined the activity and function of the lysozyme inhibitor Ivy (named IvyEt) identified in the pathogenic E. tarda strain TX01. IvyEt possesses the Ivy signature motif CKPHDC in the form of (82)CQPHNC(87) and contains several highly conserved residues, including a tryptophan (W55). For the purpose of virulence analysis, an isogenic TX01 mutant, TXivy, was created. TXivy bears an in-frame deletion of the ivyEt gene. A live infection study in a turbot (Scophthalmus maximus) model showed that, compared to TX01, TXivy exhibited attenuated overall virulence, reduced tissue dissemination and colonization capacity, an impaired ability to replicate in host macrophages, and decreased resistance against the bactericidal effect of host serum. To facilitate functional analysis, recombinant IvyEt (rIvy) and three mutant proteins, i.e., rIvyW55A, rIvyC82S, and rIvyH85D, which bear Ala, Ser, and Asp substitutions at W55, C82, and H85, respectively, were prepared. In vitro studies showed that rIvy, rIvyW55A, and rIvyH85D were able to block the lytic effect of lysozyme on a Gram-positive bacterium, whereas rIvyC82S could not do so. Likewise, rIvy, but not rIvyC82S, inhibited the serum-facilitated killing effect of lysozyme on E. tarda. In vivo analysis showed that rIvy, but not rIvyC82S, restored the lost pathogenicity of TXivy and enhanced the infectivity of TX01. Together these results indicate that IvyEt is a lysozyme inhibitor and a virulence factor that depends on the conserved C82 for biological activity.
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Affiliation(s)
- Chong Wang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yong-hua Hu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Bo-guang Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Jun Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- School of Biological Sciences, Lake Superior State University, Sault Ste Marie, Michigan, USA
| | - Li Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
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Wang C, Hu YH, Chi H, Sun L. The major fimbrial subunit protein of Edwardsiella tarda: vaccine potential, adjuvant effect, and involvement in host infection. FISH & SHELLFISH IMMUNOLOGY 2013; 35:858-865. [PMID: 23811351 DOI: 10.1016/j.fsi.2013.06.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 06/16/2013] [Accepted: 06/17/2013] [Indexed: 06/02/2023]
Abstract
Edwardsiella tarda is a Gram-negative bacterium that is reckoned one of the most severe fish pathogens. In this study, we analyzed the biological properties of the E. tarda major fimbrial subunit protein, FimA. We found that mutation of fimA resulted in defective biofilm growth, attenuated infectivity against host cells, and impaired ability to disseminate into and colonize host tissues following experimental infection. When used as a subunit vaccine, recombinant FimA (rFimA) elicited a high level of protection in turbot (Scophthalmus maximus) against lethal E. tarda challenge. Immunological analysis showed that rFimA vaccination induced production of specific serum antibodies that bound to live E. tarda via interaction with the FimA on bacterial cells, and that antibody-E. tarda interaction blocked bacterial infection. Furthermore, passive immunization of turbot with anti-rFimA serum before E. tarda infection reduced bacterial loads in fish tissues to significant extents. To examine the adjuvant potential of FimA, turbot were vaccinated with rVhhP2, a protective Vibrio harveyi antigen, in the presence or absence of rFimA. Subsequent analysis showed that the presence of rFimA significantly augmented the protectivity of rVhhP2. ELISA and quantitative real time RT-PCR showed that rFimA significantly increased rVhhP2-specific serum antibody production and enhanced the expression of immune relevant genes. Taken together, these results indicate that FimA is a virulence-associated protein that possesses vaccine as well as adjuvant potentials, and that the immunoprotectivity of FimA is most likely due to its ability to induce specific immune response that inhibits E. tarda infection.
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Affiliation(s)
- Chong Wang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China
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Zhang J, Hu YH, Xiao ZZ, Sun L. Megalocytivirus-induced proteins of turbot (Scophthalmus maximus): identification and antiviral potential. J Proteomics 2013; 91:430-43. [PMID: 23933595 DOI: 10.1016/j.jprot.2013.07.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 07/24/2013] [Accepted: 07/30/2013] [Indexed: 11/19/2022]
Abstract
UNLABELLED Megalocytivirus is an important fish pathogen with a broad host range that includes turbot. In this study, proteomic analysis was conducted to examine turbot proteins modulated in expression by megalocytivirus infection. Thirty five proteins from spleen were identified to be differentially expressed at 2days post-viral infection (dpi) and 7dpi. Three upregulated proteins, i.e. heat shock protein 70 (Hsp70), Mx protein, and natural killer enhancing factor (NKEF), were further analyzed for potential antiviral effect. For this purpose, turbot were administered separately with the plasmids pHsp70, pMx, and pNKEF, which express Hsp70, Mx, and NKEF respectively, before megalocytivirus infection. Viral dissemination and propagation in spleen were subsequently determined. The results showed that the viral loads in fish administered with pNKEF were significantly reduced. To examine the potential of Hsp70, Mx, and NKEF as immunological adjuvant, turbot were immunized with a DNA vaccine in the presence of pHsp70, pMx, or pNKEF. Subsequent analysis showed that the presence of pNKEF and pHsp70, but not pMx, significantly reduced viral infection and enhanced fish survival. Taken together, these results indicate that NKEF exhibits antiviral property against megalocytivirus, and that both NKEF and Hsp70 may be used in DNA vaccine-based control of megalocytivirus infection. BIOLOGICAL SIGNIFICANCE This study provides the first proteomic picture of turbot in response to megalocytivirus infection. We demonstrated that megalocytivirus infection modulates the expression of turbot proteins associated with various cellular functions, and that one of the upregulated proteins, NKEF, exhibits antiviral effect when overexpressed in vivo, while another upregulated protein, Hsp70, exhibits adjuvant effect when co-immunized with a DNA vaccine. These results add molecular insights into turbot immune response induced by megalocytivirus and provide candidate proteins with application potentials in the control of megalocytivirus-associated disease.
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Affiliation(s)
- Jian Zhang
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China
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Qiu R, Li J, Xiao ZZ, Sun L. Macrophage migration inhibitory factor of Sciaenops ocellatus regulates immune cell trafficking and is involved in pathogen-induced immune response. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 40:232-239. [PMID: 23545285 DOI: 10.1016/j.dci.2013.03.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 03/18/2013] [Accepted: 03/22/2013] [Indexed: 06/02/2023]
Abstract
Macrophage migration inhibitory factor (MIF) is a multi-functional cytokine involved in immunoregulation and inflammation. In this study, we examined the expression and biological function of a MIF, SoMIF, from red drum Sciaenops ocellatus. SoMIF is composed of 115 residues and shares 85-99% overall sequence identities with the MIF of a number of teleost. SoMIF expression was detected in a wide range of tissues and upregulated by bacterial and viral infection in a time-dependent manner. In head kidney (HK) leukocytes, pathogen infection induced SoMIF expression, and the expressed SoMIF was secreted into the extracellular milieu. Recombinant SoMIF (rSoMIF) purified from Escherichia coli inhibited the migration of both HK monocytes and lymphocytes, and this inhibitory effect was abolished by the presence of anti-rSoMIF antibodies. When rSoMIF was administered into red drum, it stimulated the production of reactive oxygen species in HK monocytes both in the presence and absence of pathogen infection. In vivo infection study showed that compared to untreated fish, fish pre-treated with rSoMIF before bacterial infection exhibited significantly lower bacterial loads in blood, kidney, spleen, and liver. Taken together, these results indicate that SoMIF is a secreted protein that regulates immune cell trafficking and is involved in pathogen-induced immune response.
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Affiliation(s)
- Reng Qiu
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PR China; Graduate University of the Chinese Academy of Sciences, Beijing 100049, PR China
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Zhang J, Chen L, Sun L. SmLMWPTP, a teleost low molecular weight protein tyrosine phosphatase, inhibits the immune response of peripheral blood leukocytes in a manner that depends on the conserved P-loop. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 40:103-111. [PMID: 23500512 DOI: 10.1016/j.dci.2013.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 06/01/2023]
Abstract
Protein tyrosine phosphatases (PTPs) are a family of enzymes that play a key role in cellular signal transduction. Low molecular weight PTPs (LMWPTPs) are a subfamily of PTPs that are characterized by the presence of a conserved phosphate-binding loop (P-loop) with the signature sequence of (V/I)CXGNXCRS. To date, very little study on teleost LMWPTPs has been documented, and, as a result, the function of LMWPTPs in fish is essentially unknown. In this study, we identified a LMWPTP from turbot (Scophthalmus maximus) and examined its biological activity and functionality. The turbot LMWPTP (SmLMWPTP) is composed of 158 residues and possesses a typical P-loop sequence in the form of (12)VCLGNICRS(20). Purified recombinant SmLMWPTP (rSmLMWPTP) exhibited apparent phosphatase activity, which was optimal at pH 5 and 50°C. The activity of SmLMWPTP was abolished when C13 and, in particular, R19 of the P-loop were mutated. SmLMWPTP expression was detected in a wide range of tissues and upregulated by bacterial and viral infection. Subcellular localization analysis showed that SmLMWPTP was secreted by peripheral blood leukocytes (PBL) into the extracellular milieu. When PBL were treated with rSmLMWPTP, the cells exhibited significant reductions in (i) proliferative and respiratory burst activity, (ii) expression levels of multiple immune relevant genes, and (iii) phagocytic activity. In contrast, the mutant SmLMWPTP bearing R19 mutation had no effect on PBL activity. Taken together, these results indicate that SmLMWPTP is a secreted PTP that exerts a negative regulatory effect on the innate immune response of PBL in a manner that depends on the structural integrity of the P-loop.
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Affiliation(s)
- Jian Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
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Wang C, Hu YH, Sun BG, Chi H, Li J, Sun L. Environmental isolates P1SW and V3SW as a bivalent vaccine induce effective cross-protection against Edwardsiella tarda and Vibrio anguillarum . DISEASES OF AQUATIC ORGANISMS 2013; 103:45-53. [PMID: 23482384 DOI: 10.3354/dao02569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Edwardsiella tarda and Vibrio anguillarum are severe fish pathogens. In this study, we aimed at selecting avirulent environmental isolates with application potential in the prevention of E. tarda- and V. anguillarum-associated diseases. For this purpose, we selected and analyzed 2 seawater isolates, P1SW and V3SW, belonging to the genera Pseudomonas and Vibrio, respectively. When administered to turbot Scophthalmus maximus via immersion and oral feeding, P1SW and V3SW at a dose of 2 × 108 colony-forming units caused no mortality, but both strains were able to disseminate into internal organs in a transient, time-dependent manner. When turbot were immunized with P1SW, V3SW, or P1SW plus V3SW (named P1V3) via immersion plus oral routes, the latter with vaccines embedded in sodium alginate microspheres, moderate protection against E. tarda and V. anguillarum was induced by V3SW, and moderate protection against E. tarda was induced by P1SW. Compared to P1SW and V3SW, P1V3 elicited a significantly stronger protection against both E. tarda and V. anguillarum. Immunological analysis showed that (1) P1SW, V3SW, and especially P1V3 activated head kidney macrophages, (2) P1V3 induced significantly higher levels of serum antibodies against E. tarda and V. anguillarum than P1SW and V3SW, and (3) P1V3-induced antibodies were able to bind E. tarda and V. anguillarum and enhance serum bactericidal activity. These results indicate that P1V3 as a naturally delivered vaccine elicited a humoral immune response against both E. tarda and V. anguillarum and, as a result, was cross-protective against E. tarda and V. anguillarum infection.
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Affiliation(s)
- Chong Wang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, PR China
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Li MF, Chen C, Li J, Sun L. The C-reactive protein of tongue sole Cynoglossus semilaevis is an acute phase protein that interacts with bacterial pathogens and stimulates the antibacterial activity of peripheral blood leukocytes. FISH & SHELLFISH IMMUNOLOGY 2013; 34:623-631. [PMID: 23246921 DOI: 10.1016/j.fsi.2012.12.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 12/04/2012] [Accepted: 12/04/2012] [Indexed: 06/01/2023]
Abstract
Pentraxins are a family of evolutionarily conserved proteins that play an important part in innate immunity. C-reactive protein (CRP) is a member of the pentraxin family and in humans is known to be the major acute phase protein. In this work, we report the identification and analysis of a CRP, CsCRP, from half-smooth tongue sole (Cynoglossus semilaevis). CsCRP is composed of 228 amino acid residues and possesses a Pentraxin/CRP domain. Expression of CsCRP occurred in a wide range of tissues and was upregulated by pathogen infection in kidney, spleen, blood, and, in particular, liver. Following bacterial infection, CsCRP level in blood rose rapidly within 12 h and was approximately 3.8 fold of that of the basal level. Purified recombinant CsCRP (rCsCRP) was able to interact with Gram-negative and Gram-positive bacteria including those of pathogenic nature in a dose-dependent manner. When peripheral blood leukocytes (PBL) were infected with bacterial pathogen in the presence of rCsCRP, the respiratory burst and phagocytic capacity of the cells were increased to significant extents. Taken together, these results indicate that CsCRP is an acute phase protein that plays a role in innate immune defense against bacterial infection.
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Affiliation(s)
- Mo-fei Li
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
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Yu LP, Sun BG, Li J, Sun L. Characterization of a c-type lysozyme of Scophthalmus maximus: expression, activity, and antibacterial effect. FISH & SHELLFISH IMMUNOLOGY 2013; 34:46-54. [PMID: 23063540 DOI: 10.1016/j.fsi.2012.10.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/27/2012] [Accepted: 10/01/2012] [Indexed: 06/01/2023]
Abstract
Lysozyme is a key component of the innate immune system and plays an important role in antibacterial infection. In this study, we analyzed the expression and activity of a chicken-type (c-type) lysozyme (named SmLysC) from turbot (Scophthalmus maximus). SmLysC is composed of 143 residues and shares 67-90% overall sequence identities with the c-type lysozymes of a number of teleost fish. SmLysC possesses a typical c-type lysozyme domain, which contains the conserved residues E50 and D67 that form the putative catalytic site. SmLysC expression was detected, in increasing order, in head kidney, gill, heart, muscle, brain, spleen, blood, and liver. Bacterial infection caused significant inductions of SmLysC expression in head kidney, spleen, and liver in a time-dependent manner. Immunoblot analysis indicated that SmLysC has a subcellular localization in the extracellular milieu. Recombinant SmLysC (rSmLysC) was able to bind to bacterial cells and inhibit bacterial growth. Enzyme assay showed that the optimal temperature and pH of rSmLysC were 37 °C and pH 6.0 respectively. In contrast to rSmLysC, the mutant protein rSmLysCM1, which bears alanine substitutions at E50 and D67, displayed drastically reduced bacteriolytic activity. rSmLysC was able to inhibit the growth of several fish bacterial pathogens in a manner that depended on the dose of the protein; however, Gram-positive bacteria were in general more sensitive to rSmLysC than Gram-negative bacteria. Together these results indicate that SmLysC is a functional lysozyme that is likely to participate in innate immune defense against extracellular bacterial pathogens, in particular those of Gram-positive nature.
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Affiliation(s)
- Lan-ping Yu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
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