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Panji Z, Nadoushan MJ, Fekrirad Z, Rasooli I. Modulation with anti-Oma87 antibodies of cytotoxicity, adherence, and internalization of Acinetobacter baumannii in human cervical carcinoma epithelial cells. APMIS 2024. [PMID: 39223818 DOI: 10.1111/apm.13465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Accepted: 08/12/2024] [Indexed: 09/04/2024]
Abstract
BamA, an Omp85 superfamily member, is universally conserved and essential for cell viability. Using anti-Oma87 antibodies, we focus on understanding the effect of Oma87 of Acinetobacter baumannii on pathogenicity. Oma87 was expressed, purified, and used to induce anti-Oma87 antibodies in BALB/c mice. Acute toxicity of the protein was evaluated in mice. HeLa cells were infected with both live and killed A. baumannii 19606 and a clinical isolate. The effects of anti-Oma87 sera on A. baumannii adherence, internalization, and proliferation in HeLa cells were studied. The roles of microfilaments and microtubules in A. baumannii invasion were demonstrated by Actin disruption. Reduced bacterial population and biofilm formation were noted. The ability of A. baumannii to provoke autophagy through Oma87 induction leads to incomplete autophagy and potentially facilitates bacterial replication. Actin-mediated uptake, attachment, and invasion demonstrated A. baumannii survival and multiplication within vacuoles in the host cell. The findings underscore the potential of Oma87 as a therapeutic intervention target in infections caused by A. baumannii. This comprehensive analysis contributes valuable information for understanding the virulence mechanisms of A. baumannii, potentially guiding future strategies to combat infections caused by this pathogen.
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Affiliation(s)
- Zahra Panji
- Department of Biology, Shahed University, Tehran, Iran
| | - Mohammadreza Jalali Nadoushan
- Department of Pathology, School of Medicine, Shahed University, Tehran, Iran
- Molecular Microbiology Research Center and Department of Biology, Shahed University, Tehran, Iran
| | | | - Iraj Rasooli
- Department of Biology, Shahed University, Tehran, Iran
- Molecular Microbiology Research Center and Department of Biology, Shahed University, Tehran, Iran
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Panickar A, Manoharan A, Anbarasu A, Ramaiah S. Respiratory tract infections: an update on the complexity of bacterial diversity, therapeutic interventions and breakthroughs. Arch Microbiol 2024; 206:382. [PMID: 39153075 DOI: 10.1007/s00203-024-04107-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 07/30/2024] [Accepted: 08/09/2024] [Indexed: 08/19/2024]
Abstract
Respiratory tract infections (RTIs) have a significant impact on global health, especially among children and the elderly. The key bacterial pathogens Streptococcus pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae, Staphylococcus aureus and non-fermenting Gram Negative bacteria such as Acinetobacter baumannii and Pseudomonas aeruginosa are most commonly associated with RTIs. These bacterial pathogens have evolved a diverse array of resistance mechanisms through horizontal gene transfer, often mediated by mobile genetic elements and environmental acquisition. Treatment failures are primarily due to antimicrobial resistance and inadequate bacterial engagement, which necessitates the development of alternative treatment strategies. To overcome this, our review mainly focuses on different virulence mechanisms and their resulting pathogenicity, highlighting different therapeutic interventions to combat resistance. To prevent the antimicrobial resistance crisis, we also focused on leveraging the application of artificial intelligence and machine learning to manage RTIs. Integrative approaches combining mechanistic insights are crucial for addressing the global challenge of antimicrobial resistance in respiratory infections.
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Affiliation(s)
- Avani Panickar
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, 632014, India
- Department of Bio-Sciences, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, 632014, India
| | - Anand Manoharan
- Infectious Diseases Medical and Scientific Affairs, GlaxoSmithKline (GSK), Worli, Maharashtra, India
| | - Anand Anbarasu
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, 632014, India
- Department of Biotechnology, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, 632014, India
| | - Sudha Ramaiah
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, 632014, India.
- Department of Bio-Sciences, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, 632014, India.
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Negahdari B, Sarkoohi P, Ghasemi Nezhad F, Shahbazi B, Ahmadi K. Design of multi-epitope vaccine candidate based on OmpA, CarO and ZnuD proteins against multi-drug resistant Acinetobacter baumannii. Heliyon 2024; 10:e34690. [PMID: 39149030 PMCID: PMC11324976 DOI: 10.1016/j.heliyon.2024.e34690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 07/12/2024] [Accepted: 07/15/2024] [Indexed: 08/17/2024] Open
Abstract
Acinetobacter baumannii has been identified as a major cause of nosocomial infections. Acinetobacter infections are often difficult to treat with multidrug resistant phenotypes. One of the most effective ways to combat infectious diseases is through vaccination. In this study, an attempt was made to select the most protective and potent immunostimulatory epitopes based on the epitope-rich domains of the ZnuD, OmpA and CarO proteins of Acinetobacter baumannii to design a vaccine that can protect against this infection. After predicting the epitope of B- and T-cells, seven antigenic regions of three proteins CarO, ZnuD and OmpA, were selected. These regions were bound by a GGGS linker. The binding affinity and molecular interactions of the vaccine with the immune receptors TLR2 and TLR4 were studied using molecular docking analysis. This vaccine design was subjected to in silico immune simulations using C-ImmSim. The designed vaccine was highly antigenic, non-allergenic and stable. TLR2 and TLR4 were selected to analyze the ability of the modeled chimeric protein to interact with immune system receptors. The results showed strong interaction between the designed protein vaccine with TLR2 (-18.8 kcal mol-1) and TLR4 (-15.1 kcal mol-1). To verify the stability of the interactions and the structure of the designed protein, molecular dynamics (MD) simulations were performed for 200 ns. Various analyses using MD showed that the protein structure is stable alone and in interaction with TLR2 and TLR4. The ability of the vaccine candidate protein to stimulate the immune system to produce the necessary cytokines and antibodies against Acinetobacter baumannii was also demonstrated by the ability of the protein designed using the C-ImmSim web server to induce an immune response. Therefore, the designed protein vaccine may be a suitable candidate for in vivo as well as in vitro studies against Acinetobacter baumannii infections.
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Affiliation(s)
- Batul Negahdari
- Student Research Committee, Faculty of Pharmacy, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Parisa Sarkoohi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Forozan Ghasemi Nezhad
- Student Research Committee, Faculty of Pharmacy, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Behzad Shahbazi
- School of Pharmacy, Semnan University of Medical Sciences, Semnan, Iran
- Nervous System Stem Cells Research Center, Semnan University of Medical Sciences, Semnan, Iran
| | - Khadijeh Ahmadi
- Infectious and Tropical Diseases Research Center, Hormozgan Health Institute, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
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Shang K, Zhu Y, Tian T, Shi H, Yin Z, He Y, Shi J, Ding J, Zhang F. Development of a novel multi-epitope vaccine for brucellosis prevention. Heliyon 2024; 10:e34721. [PMID: 39148966 PMCID: PMC11325379 DOI: 10.1016/j.heliyon.2024.e34721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 07/14/2024] [Accepted: 07/15/2024] [Indexed: 08/17/2024] Open
Abstract
Brucellosis, a zoonotic disease caused by Brucella, presents a significant threat to both animal and human health. In animals, the disease can lead to infertility, miscarriage, and high fever, while in humans, symptoms may include recurrent fever, fatigue, sweating, hepatosplenomegaly, and joint and muscle pain following infection. Treatment often involves long-term antibiotic therapy, placing a substantial psychological and financial burden on patients. While vaccination is crucial for prevention, current animal vaccines have drawbacks such as residual virulence, and a safe and effective human vaccine is lacking. Hence, the development of a vaccine for brucellosis is imperative. In this study, we utilized bioinformatics methods to design a multi-epitope vaccine targeting Brucella. Targeting Heme transporter BhuA and polysaccharide export protein, we identified antigenic epitopes, including six cytotoxic T lymphocyte (CTL) dominant epitopes, six helper T lymphocyte (HTL) dominant epitopes, one conformation B cell dominant epitope, and three linear B cell dominant epitopes. By linking these epitopes with appropriate linkers and incorporating a Toll-like receptor (TLR) agonist (human beta-defensin-2) and an auxiliary peptide (Pan HLA-DR epitopes), we constructed the multi-epitope vaccine (MEV). The MEV demonstrated high antigenicity, non-toxicity, non-allergenicity, non-human homology, stability, and solubility. Molecular docking analysis and molecular dynamics simulations confirmed the interaction and stability of the MEV with receptors (MHCI, MHCII, TLR4). Codon optimization and in silico cloning validated the translation efficiency and successful expression of MEV in Escherichia coli. Immunological simulations further demonstrated the efficacy of MEV in inducing robust immune responses. In conclusion, our findings suggest that the engineered MEVs have the potential to stimulate both humoral and cellular immune responses, offering valuable insights for the future development of safe and efficient Brucella vaccines.
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Affiliation(s)
- Kaiyu Shang
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, 830011, PR China
| | - Yuejie Zhu
- Reproductive Medicine Center, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, 830011, PR China
| | - Tingting Tian
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, 830011, PR China
| | - Huidong Shi
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, 830011, PR China
| | - Zhengwei Yin
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, 830011, PR China
| | - Yueyue He
- Department of Immunology, School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, Xinjiang, 830011, PR China
| | - Juan Shi
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, 830011, PR China
| | - Jianbing Ding
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, 830011, PR China
| | - Fengbo Zhang
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, 830011, PR China
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Buchhorn de Freitas S, Clair Pinto Seixas Neto A, Aparecido Panagio L, Pereira Soares M, Drawanz Hartwig D. Hypothetical adhesin CAM87009.1 formulated in alum or biogenic silver nanoparticles protects mice from lethal infection by multidrug-resistant Acinetobacter baumannii. Vaccine 2024; 42:3802-3810. [PMID: 38719690 DOI: 10.1016/j.vaccine.2024.04.094] [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: 09/13/2023] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 06/14/2024]
Abstract
Due to its antimicrobial resistance characteristics, the World Health Organization (WHO) classifies A. baumannii as one of the critical priority pathogens for the development of new therapeutic strategies. Vaccination has been approached as an interesting strategy to overcome the lack of effective antimicrobials and the long time required to develop and approve new drugs. In this study, we aimed to evaluate as a vaccine the hypothetical adhesin protein CAM87009.1 in its recombinant format (rCAM87009.1) associated with aluminum hydroxide (Alhydrogel®) or biogenic silver nanoparticles (bio-AgNP) as adjuvant components against lethal infection by A. baumannii MDR strain. Both vaccine formulations were administered in three doses intramuscularly in BALB/c murine models and the vaccinated animals were tested in a challenge assay with A. baumannii MDR strain (DL100). rCAM87009.1 protein associated with both adjuvants was able to protect 100 % of animals challenged with the lethal strain during the challenge period. After the euthanasia of the animals, no A. baumannii colonies were detected in the lungs of animals vaccinated with the rCAM87009.1 protein in both formulations. Since the first immunization, high IgG antibody titers were observed (1:819,200), with results being statistically similar in both vaccine formulations evaluated. rCAM87009.1 associated with both adjuvants was capable of inducing at least one class of isotypes associated with the processes of neutralization (IgG2b and IgA for bio-AgNP and Alhydrogel®, respectively), opsonization (IgG1 in both vaccines) and complement activation (IgM and IgG3 for bio-AgNP and Alhydrogel®, respectively). Furthermore, reduced tissue damage was observed in animals vaccinated with rCAM87009.1 + bio-AgNP when compared to animals vaccinated with Alhydrogel®. Our results indicate that the rCAM87009.1 protein associated with both bio-AgNP and Alhydrogel® are combinations capable of promoting immunity against infections caused by A. baumannii MDR. Additionally, we demonstrate the potential of silver nanoparticles as alternative adjuvant molecules to the use of aluminum salts.
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Affiliation(s)
- Stella Buchhorn de Freitas
- Center of Technological Development, Biotechnology, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil; Department of Microbiology and Parasitology, Biology Institute, Federal University of Pelotas, Pelotas, RS, Brazil
| | | | | | - Mauro Pereira Soares
- Regional Diagnostic Laboratory, Veterinary College, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Daiane Drawanz Hartwig
- Center of Technological Development, Biotechnology, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil; Department of Microbiology and Parasitology, Biology Institute, Federal University of Pelotas, Pelotas, RS, Brazil.
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Rajangam SL, Narasimhan MK. Current treatment strategies for targeting virulence factors and biofilm formation in Acinetobacter baumannii. Future Microbiol 2024; 19:941-961. [PMID: 38683166 PMCID: PMC11290764 DOI: 10.2217/fmb-2023-0263] [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: 11/24/2023] [Accepted: 03/20/2024] [Indexed: 05/01/2024] Open
Abstract
A higher prevalence of Acinetobacter baumannii infections and mortality rate has been reported recently in hospital-acquired infections (HAI). The biofilm-forming capability of A. baumannii makes it an extremely dangerous pathogen, especially in device-associated hospital-acquired infections (DA-HAI), thereby it resists the penetration of antibiotics. Further, the transmission of the SARS-CoV-2 virus was exacerbated in DA-HAI during the epidemic. This review specifically examines the complex interconnections between several components and genes that play a role in the biofilm formation and the development of infections. The current review provides insights into innovative treatments and therapeutic approaches to combat A. baumannii biofilm-related infections, thereby ultimately improving patient outcomes and reducing the burden of HAI.
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Affiliation(s)
- Seetha Lakshmi Rajangam
- Department of Genetic Engineering, School of Bioengineering, College of Engineering & Technology, SRM Institute of Science & Technology, Kattankulathur, Chennai, Tamil Nadu, 603203, India
| | - Manoj Kumar Narasimhan
- Department of Genetic Engineering, School of Bioengineering, College of Engineering & Technology, SRM Institute of Science & Technology, Kattankulathur, Chennai, Tamil Nadu, 603203, India
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Chen L, Liu S, Zhang Y, Tang Q, Quan C, Wang J, Peng X, Zhong X. Palmitic acid-capped MIL-101-Al as a nano-adjuvant to amplify immune responses against Pseudomonas aeruginosa. NANOSCALE 2024; 16:10306-10317. [PMID: 38727538 DOI: 10.1039/d4nr01180e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
As a highly contagious opportunistic pathogen, Pseudomonas aeruginosa (P. aeruginosa) is one of the main causes of healthcare-associated infections. The drug-resistant nature of P. aeruginosa can render antibiotic treatments ineffective, leading to a high morbidity and mortality. Higher specificity and reduced toxicity are features of immunotherapy, which can generate robust immune responses and preserve long-term immunological memory to completely eradicate infections. In this study, we developed a type of P. aeruginosa vaccine based on a metal-organic framework. Specifically, MIL-101-Al nanoparticles were synthesized to encapsulate antigens derived from the bacterial lysate (BL) of PAO1, a drug-resistant P. aeruginosa, and the adjuvant unmethylated cytosine-phosphate-guanine oligonucleotide (CpG), which were then modified with palmitic acid (PAA) to obtain MIL-BC@PAA. The stability and biocompatibility were significantly increased by capping with PAA. Moreover, MIL-BC@PAA showed significantly enhanced uptake by antigen presenting cells (APCs), and promoted their maturation. Importantly, immunity studies revealed the greatly elicited antigen-specific humoral and cellular responses, and a protection rate of about 70% was observed in P. aeruginosa-challenged mice. Overall, these results demonstrate the promising potential of MIL-BC@PAA as an ideal nanovaccine for P. aeruginosa vaccination.
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Affiliation(s)
- Lingming Chen
- Guangdong Provincial Key Laboratory of Medical Molecular Diagnostics, The First Dongguan Affiliated Hospital, Guangdong Medical University, 523808 Dongguan, Guangdong, China
- Institute of Laboratory Medicine, School of Medical Technology, Guangdong Medical University, 523808 Dongguan, Guangdong, China
| | - Shuai Liu
- Otolaryngology Department, Huangjiang Hospital, Dongguan 523750, China
| | - Yunting Zhang
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Qiling Tang
- Guangdong Provincial Key Laboratory of Research and Development of Natural Drugs, School of Pharmacy, Guangdong Medical University, Dongguan 523808, China.
| | - Chunyu Quan
- Guangdong Provincial Key Laboratory of Research and Development of Natural Drugs, School of Pharmacy, Guangdong Medical University, Dongguan 523808, China.
| | - Jundan Wang
- Jiangxi College of Traditional Chinese Medicine, Nanchang 330004, China
| | - Xinsheng Peng
- Guangdong Provincial Key Laboratory of Research and Development of Natural Drugs, School of Pharmacy, Guangdong Medical University, Dongguan 523808, China.
| | - Xiaofang Zhong
- Guangdong Provincial Key Laboratory of Research and Development of Natural Drugs, School of Pharmacy, Guangdong Medical University, Dongguan 523808, China.
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Shi J, Cheng J, Liu S, Zhu Y, Zhu M. Acinetobacter baumannii: an evolving and cunning opponent. Front Microbiol 2024; 15:1332108. [PMID: 38318341 PMCID: PMC10838990 DOI: 10.3389/fmicb.2024.1332108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/08/2024] [Indexed: 02/07/2024] Open
Abstract
Acinetobacter baumannii is one of the most common multidrug-resistant pathogens causing nosocomial infections. The prevalence of multidrug-resistant A. baumannii infections is increasing because of several factors, including unregulated antibiotic use. A. baumannii drug resistance rate is high; in particular, its resistance rates for tigecycline and polymyxin-the drugs of last resort for extensively drug-resistant A. baumannii-has been increasing annually. Patients with a severe infection of extensively antibiotic-resistant A. baumannii demonstrate a high mortality rate along with a poor prognosis, which makes treating them challenging. Through carbapenem enzyme production and other relevant mechanisms, A. baumannii has rapidly acquired a strong resistance to carbapenem antibiotics-once considered a class of strong antibacterials for A. baumannii infection treatment. Therefore, understanding the resistance mechanism of A. baumannii is particularly crucial. This review summarizes mechanisms underlying common antimicrobial resistance in A. baumannii, particularly those underlying tigecycline and polymyxin resistance. This review will serve as a reference for reasonable antibiotic use at clinics, as well as new antibiotic development.
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Affiliation(s)
- Jingchao Shi
- Open Laboratory Medicine, Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
- Department of Clinical Laboratory, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, China
- Graduate School, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jianghao Cheng
- Open Laboratory Medicine, Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
| | - Shourong Liu
- Department of Infectious Disease, Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
| | - Yufeng Zhu
- Open Laboratory Medicine, Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
| | - Mingli Zhu
- Open Laboratory Medicine, Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
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Mansouri M, Sadeghpoor M, Jahangiri A, Ghaini MH, Rasooli I. Enhanced immunoprotection against Acinetobacter baumannii infection: Synergistic effects of Bap and BauA in a murine model. Immunol Lett 2023; 262:18-26. [PMID: 37652189 DOI: 10.1016/j.imlet.2023.08.004] [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: 05/31/2023] [Revised: 08/26/2023] [Accepted: 08/28/2023] [Indexed: 09/02/2023]
Abstract
BACKGROUND The rise of multi-drug resistant Acinetobacter baumannii poses a grave threat to hospital settings, resulting in increased mortality rates and garnering global attention. The formation of biofilms facilitated by biofilm-associated protein (Bap) and the iron absorption capabilities mediated by Baumannii acinetobactin utilization A (BauA) contribute to the persistence and survival of multidrug-resistant strains. In this study, we aimed to investigate the potential of disrupting the function of BauA and Bap simultaneously as a strategy for controlling A. baumannii. METHODS Recombinant Bap and BauA were expressed, purified, and subcutaneously administered individually and in combination to BALB/c mice. Subsequently, mice were intraperitoneally challenged with A. baumannii, and the bacterial load and tissue damage in the spleen, lung, and liver were assessed. Serum samples were evaluated to determine antibody titers in surviving mice. RESULTS Specific IgG antibodies were significantly increased. A combination of the antigens resulted in enhanced titer of specific IgGs in comparison to either BauA or Bap alone. The antibodies remained stable over a seven-month period. The combination of Bap and BauA exhibited superior immunoprotection against A. baumannii infection compared to individual administration, resulting in a further reduction in bacterial load in the liver, spleen, and lungs. The histopathological analysis demonstrated successful protection of the tissues against A. baumannii-induced damage upon administration of the two immunogens. CONCLUSIONS The combination of Bap and BauA has the potential to target a broader range of A. baumannii strains, including those expressing either Bap or BauA, thereby increasing its efficacy against a diverse array of strains.
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Affiliation(s)
| | | | - Abolfazl Jahangiri
- Applied Microbiology Research Center, Systems biology and poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | | | - Iraj Rasooli
- Department of Biology, Shahed University, Tehran, Iran; Molecular Microbiology Research Center and Department of Biology, Shahed University, Tehran, Iran.
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Heidarinia H, Tajbakhsh E, Rostamian M, Momtaz H. Epitope mapping of Acinetobacter baumannii outer membrane protein W (OmpW) and laboratory study of an OmpW-derivative peptide. Heliyon 2023; 9:e18614. [PMID: 37560650 PMCID: PMC10407128 DOI: 10.1016/j.heliyon.2023.e18614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/12/2023] [Accepted: 07/24/2023] [Indexed: 08/11/2023] Open
Abstract
Outer membrane protein W (OmpW) is a less-known A. baumannii antigen with potential immunogenic properties. The epitopes of this protein are not well-identified yet. Therefore, in the present study, B- and T-cell epitopes of A. baumannii OmpW were found using comprehensive in silico and partially in vitro studies. The T-cell (both class-I and class-II) and B-cell (both linear and conformational) epitopes were predicted and screened through many bioinformatics approaches including the prediction of IFN-γ production, immunogenicity, toxicity, allergenicity, human similarity, and clustering. A single 15-mer epitopic peptide containing a linear B-cell and both classes of T-cell epitopes were found and used for further assays. For in vitro assays, patient- and healthy control-derived peripheral blood mononuclear cells were stimulated with the 15-mer peptide, Phytohemagglutinin, or medium alone, and cell proliferation and IFN-γ production assays were performed. The bioinformatics studies led to mapping OmpW epitopes and introducing a 15-mer peptide. In vitro assays to some extent showed its potency in cell proliferation but not in IFN-γ induction, although the responses were not very expressive and faced some questions/limitations. In general, in the current study, we mapped the most immunogenic epitopes of OmpW that may be used for future studies and also assayed one of these epitopes in vitro, which was shown to have an immunogenicity potential. However, the induced immune responses were not strong which suggests that the present peptide needs a series of biotechnological manipulations to be used as a potential vaccine candidate. More studies in this field are recommended.
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Affiliation(s)
- Hana Heidarinia
- Department of Microbiology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
| | - Elahe Tajbakhsh
- Department of Microbiology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
| | - Mosayeb Rostamian
- Infectious Diseases Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Hassan Momtaz
- Department of Microbiology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
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