Immunoprotective evaluation of &lt;I&gt;Escherichia coli&lt;/I&gt; outer membrane protein A against the main pathogens of animal mastitis

Chen, Chen; Wu, Nayiyuan; Na, Rong; Kang, Can; Chen, Chunlin; Wu, Sanqiao; Liu, Xiang; Zhang, Xiaoying

doi:10.4314/tjpr.v19i1.23

Cited by 6 publications

(10 citation statements)

References 17 publications

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“…S. aureus possesses a round shape for convenient counting and has been widely used in the analysis of leukocyte phagocytosis, is also a major etiologic agent of cow mastitis [ 1 ], and immunization with NP-OmpA may boost resistance to S. aureus infection. Moreover, we found that antiserum from animals immunized with NP-OmpA recognized with E. coli , which suggested that anti-NP-OmpA antibodies and E. coli formed antigen-antibody complexes and likely enhanced antigen presentation [ 15 ]. Antibodies from mice immunized with NP-OmpA also bound to OmpA at a higher titer (3200) than those from mice immunized with OmpA.…”

Section: Discussionmentioning

confidence: 99%

“…Anti-OmpA antibodies can regulate the function of specific phagocytosis to protect against E. coli infection [ 14 ]. We found that OmpA had significant protective rates of 58.33% and 46.15% against E. coli and Staphylococcus aureus, respectively, and the OmpA fragment is also immunogenic [ 15 ]. Therefore, OmpA is a vaccine candidate for the prevention of E. coli infection.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Escherichia coli OmpA Oral Nanoparticles and Evaluation of Immune Functions against the Major Etiologic Agent of Cow Mastitis

Liu

Sun

et al. 2021

Vaccines

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Escherichia coli is a major etiologic agent of cow mastitis, a condition that results in huge economic losses. There is a lack of an oral vaccine for cow mastitis. Previous studies have confirmed that the outer membrane protein A (OmpA) of E. coli is immunogenic and can be used for vaccine design. In the present study, OmpA was encapsulated into nanoparticles (NP-OmpA) for an oral vaccine for cow mastitis. Methods: OmpA was purified with Ni-NTA flow resin and encapsulated with chitosan (CS) to prepare NP-OmpA nanoparticles. The gastrointestinal tract was simulated in vitro (PBS, pH 1.2) to measure the protein release rate. The optimal preparation conditions for NP-OmpA were determined by analyzing the concentrations of OmpA and CS, magnetic mixing speed, mixing time, and the ratio of tripolyphosphate (TPP)/CS (w/w). NP-OmpA safety was assessed by function factors and histopathological examination of livers and kidneys. The immune activity of NP-OmpA was determined using qRT-PCR to assess immune-related gene expression, leukocyte phagocytosis of Staphylococcus aureus, ELISA to evaluate antiserum titer and immune recognition of E. coli, and the organ index. The immune protection function of NP-OmpA was assessed by the protection rate of NP-OmpA to E. coli in mice, qRT-PCR for inflammation-related gene expression, assay kits for antioxidant factors, and visceral injury in the histopathological sections. Results: NP-OmpA nanoparticles had a diameter of about 700 nm, loading efficiency (LE) of 79.27%, and loading capacity (LC) of 20.31%. The release rate of NP-OmpA (0~96 h) was less than 50% in vitro. The optimal preparation conditions for NP-OmpAs were OmpA protein concentration of 2 mg/mL, CS concentration of 5 mg/mL, TPP/CS (w/w) of 1:1, magnetic mixing speed of 150 r/min, and mixing time of 15 min. Histopathological sections and clinical analytes of uric acid (UA), creatinine (Cr), alanine aminotransferase (ALT), aspartate transaminase (AST), catalase (CAT), glutathione (GSH), and malondialdehyde (MDA) showed NP-OmpA did not damage mice livers or kidneys. NP-OmpA could enhance the immune-related gene expression of IFN-γ and HSP70 in the spleen, liver, and kidney and the leukocyte phagocytosis of S. aureus. The antiserum titer (1:3200) was obtained from mice immunized with NP-OmpA, which had an immune recognition effect to E. coli. The immune protection rate of NP-OmpA was 71.43% (p < 0.05) to E. coli. NP-OmpA could down-regulate the inflammation-related gene expression of TNF-a, IL-6, and IL-10 in the spleen, liver, and kidney, and the antioxidant factors MDA and SOD in the liver, and reduce injury in the liver and kidney of mice induced by E. coli. Conclusions: A novel NP-OmpA nanoparticle was encapsulated, and the optimal preparation conditions were determined. The NP-OmpA was safe and had good immune functions. They are expected to induce a response that resists infection with the major etiologic agent (E. coli) of cow mastitis.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of Escherichia coli OmpA Oral Nanoparticles and Evaluation of Immune Functions against the Major Etiologic Agent of Cow Mastitis

Liu

Sun

et al. 2021

Vaccines

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“…S. aureus is also a major causative agent of cow mastitis [1], and immunization with NP-OmpA may boost resistance to S. aureus infection. Moreover, we found that antiserum from animals immunized with NP-OmpA interacts with E. coli, which suggests that anti-NP-OmpA antibodies and E. coli formed antigen-antibody complexes and likely enhanced antigen presentation [15]. Also, antibodies from mice immunized with NP-OmpA bound to OmpA at a higher titer (1: 3200) than those from mice immunized with OmpA.…”

Section: Discussionmentioning

confidence: 81%

“…Anti-OmpA antibodies can regulate the function of speci c phagocytosis to protect against E. coli infection [14]. We found that OmpA had signi cant protective rates of 58.33% and 46.15% against E. coli and Staphylococcus aureus, respectively, the pathogenic bacteria of cow mastitis, and that the OmpA fragment is also immunogenic [15]. Therefore, OmpA is a vaccine candidate for the prevention of E. coli infection.…”

Section: Introductionmentioning

confidence: 84%

Synthesis of Escherichia coli OmpA oral nanoparticles and evaluation of immune function against the main pathogenic bacteria of cow mastitis

Liu¹,

Sun²,

Wu³

et al. 2021

Preprint

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Background: Escherichia coli is a main pathogenic bacteria that causes cow mastitis, a condition that results in huge economic losses. There is lack of orally delivered prevention for cow mastitis. The outer membrane protein A (OmpA) of E. coli is immunogenic and can be used in a vaccine. In the present study, OmpA was synthesized into nanoparticles (NP-OmpA) for oral delivery and prevention of cow mastitis.Methods: OmpA was purified with Ni-NTA flow resin and encapsulated with chitosan (CS) to prepare NP-OmpA nanoparticles. The gastrointestinal tract was simulated in vitro (PBS, pH 1.2) to measure the protein release rate. The optimal preparation conditions for NP-OmpA were determined by analyzing the concentrations of OmpA and CS, magnetic mixing speed, mixing time, and ratio of tripolyphosphate (TPP)/CS (W/W). NP-OmpA safety was detected by function factors and histopathological examination of livers and kidneys. Immune activity of NP-OmpA was determined using qRT-PCR to detect immune-related gene expression, leukocyte phagocytosis of Staphylococcus aureus, ELISA to detect antiserum titer and immune recognition of E. coli, and the organ index. The immune protection function of NP-OmpA was assessed by the protection rate of NP-OmpA to E. coli in mice, qRT-PCR for inflammation-related gene expression, assay kits for antioxidant factors, and visceral injury in the histopathological sections. Results: NP-OmpA nanoparticles had a nanodiameter of about 700 nm, loading efficiency (LE) of 79.27%, and loading capacity (LC) of 20.31%. The release rate was less than 50% in vitro. The optimal preparation conditions for NP-OmpA were OmpA protein concentration of 2 mg/mL, CS concentration of 5 mg/mL, TPP/CS (W/W) of 1:1, magnetic mixing speed of 150 r/min, and mixing time of 15 min. Histopathological sections and factors of uric acid (UA), creatinine (Cr), alanine aminotransferase (ALT), aspartate transaminase (AST), catalase (CAT), glutathione (GSH), and malondialdehyde (MDA) showed NP-OmpA was safe for mice liver and kidney. NP-OmpA could enhance the immune-related gene expression of IFN-γ and HSP70 in the spleen, liver, and kidney, and the leukocyte phagocytosis of S. aureus. The antiserum titer (1: 3200) was obtained from mice immunized with NP-OmpA, which had an immune recognition effect to E. coli. The immune protection rate of NP-OmpA was 71.43% (p < 0.05) to E. coli. NP-OmpA could down regulate the inflammation-related gene expression of TNF-a, IL-6, and IL-10 in the spleen, liver, and kidney, and the antioxidant factors MDA and SOD in the liver, and reduce the injury in mice liver and kidney induced by E. coli. Conclusion: A novel NP-OmpA nanoparticle was synthesized, and the optimal preparation conditions were determined. The nanoparticles were found to be safer and have better immune function. They are expected to induce a response that resists infection with the main pathogenic bacteria (E. coli) of cow mastitis.

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“…Then mice plasma was used for leukocyte phagocytosis analysis directly. In addition, the serum was harvested with 300 r/min centrifugation after 4℃ overnight for immunology analysis (Chen et al 2020).…”

Section: Preparation and Specific Analysis Of Polyclonal Antibodymentioning

confidence: 99%

Immune responses and protective efficacy of outer membrane protein ExbB of Pseudomonas fluorescens against Aeromonas hydrophila and Pseudomonas fluorescens affecting Carassius auratus

Sun

Jian

et al. 2021

Aquacult Int

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The outer membrane protein (ExbB) of Pseudomonas fluorescens present in the outermost layer may possess immune functions and potential applications in subunit vaccines. ExbB bioinformatic analysis elucidated that the relationship among Pseudomonas species was closer than others, and anti-ExbB serum might provide cross-protective ability to resist Pseudomonas bacterial infection in animals. ExbB was obtained via molecular cloning, prokaryotic expression, and purification. The optimal expression conditions were a strain OD 600 value of 1.0 and IPTG concentration of 0.3 mmol/L, inducing time of 3 h, and inducing temperature of 32℃. Mice immunized to ExbB could significantly increase (p < 0.05) the spleen index and leukocyte phagocytosis parameters such as phagocytic percentage (PP) and phagocytic index (PI). The specific antiserum titer (1:12,800) was obtained, which had an in vitro immune recognition effect on both P. fluorescens and Aeromonas hydrophila. Passive immunization results for anti-ExbB mouse serum to Carassius auratus showed that ExbB serum could significantly enhance PP (p < 0.05) and PI (p < 0.05). Moreover, the passive protective rate of anti-ExbB serum against P. fluorescens infection was 54% (p < 0.05), and the passive cross-protective rate against A. hydrophila was 38.4% (p < 0.05). Furthermore, the expression of immune-related genes such as IL-6, IL-8, IL-1β, and TNF-α was significantly decreased (p < 0.05) in kidneys and gills after challenging with P. fluorescens, while the downward trend was not obvious after challenging with A. hydrophila. The trend changes of antioxidant-related factors such as malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) were not obvious after bacterial challenge. Interestingly, there was a significant reduction in the histopathological lesions in the kidney, spleen, and intestine of C. auratus challenged by P. fluorescens and A. hydrophila. Altogether, the results suggest that ExbB has an immune function in passive protection against P. fluorescens and passive cross-protection against A. hydrophila and can boost resistance to infection against the most dangerous bacterial pathogens infecting freshwater fish.

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Immunoprotective evaluation of <I>Escherichia coli</I> outer membrane protein A against the main pathogens of animal mastitis

Cited by 6 publications

References 17 publications

Synthesis of Escherichia coli OmpA Oral Nanoparticles and Evaluation of Immune Functions against the Major Etiologic Agent of Cow Mastitis

Synthesis of Escherichia coli OmpA Oral Nanoparticles and Evaluation of Immune Functions against the Major Etiologic Agent of Cow Mastitis

Synthesis of Escherichia coli OmpA oral nanoparticles and evaluation of immune function against the main pathogenic bacteria of cow mastitis

Immune responses and protective efficacy of outer membrane protein ExbB of Pseudomonas fluorescens against Aeromonas hydrophila and Pseudomonas fluorescens affecting Carassius auratus

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