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Singh KKB, Salleh MZ, Ahmed N, Yean Yean C, Ismail A. Identification and analysis of immunoreactive proteins of Shigella flexneri in human sera and stool specimens. PeerJ 2024; 12:e17498. [PMID: 38827305 PMCID: PMC11141557 DOI: 10.7717/peerj.17498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 05/10/2024] [Indexed: 06/04/2024] Open
Abstract
Background The method currently available to diagnose shigellosis is insensitive and has many limitations. Thus, this study was designed to identify specific antigenic protein(s) among the cell surface associated proteins (SAPs) of Shigella that would be valuable in the development of an alternative diagnostic assay for shigellosis, particularly one that could be run using a stool sample rather than serum. Methods The SAPs of clinical isolates of S. dysenteriae, S. boydii, Shigella flexneri, and S. sonnei were extracted from an overnight culture grown at 37 °C using acidified-glycine extraction methods. Protein profiles were observed by SDS-PAGE. To determine if antibodies specific to certain Shigella SAPs were present in both sera and stool suspensions, Western blot analysis was used to detect the presence of IgA, IgG, and IgM. Results Immunoblot analysis revealed that sera from patients infected with S. flexneri recognized 31 proteins. These SAP antigens are recognized by the host humoral response during Shigella infection. Specific antibodies against these antigens were also observed in intestinal secretions of shigellosis patients. Of these 31 S. flexneri proteins, the 35 kDa protein specifically reacted against IgA present in patients' stool suspensions. Further study illustrated the immunoreactivity of this protein in S. dysenteriae, S. boydii, and S. sonnei. This is the first report that demonstrates the presence of immunoreactive Shigella SAPs in stool suspensions. The SAPSs could be very useful in developing a simple and rapid serodiagnostic assay for shigellosis directly from stool specimens.
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Affiliation(s)
- Kirnpal Kaur Banga Singh
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
| | - Mohd Zaki Salleh
- Integrative Pharmacogenomics Institute (iPROMISE), UiTM Puncak Alam Campus, Bandar Puncak Alam, Puncak Alam, Selangor, Malaysia
| | - Naveed Ahmed
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
| | - Chan Yean Yean
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
| | - Asma Ismail
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
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Desalegn G, Tamilselvi CS, Lemme-Dumit JM, Heine SJ, Dunn D, Ndungo E, Kapoor N, Oaks EV, Fairman J, Pasetti MF. Shigella virulence protein VirG is a broadly protective antigen and vaccine candidate. NPJ Vaccines 2024; 9:2. [PMID: 38167387 PMCID: PMC10761965 DOI: 10.1038/s41541-023-00797-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 12/08/2023] [Indexed: 01/05/2024] Open
Abstract
Diarrhea caused by Shigella has been associated with high morbidity and mortality in young children worldwide. There are no licensed vaccines, and those clinically advanced have restricted coverage as they elicit serotype-specific immunity while disease is caused by multiple circulating serotypes. Our group had previously reported a close association between serum antibodies to the Shigella virulence factor VirG (or IcsA) and clinical protection in infected individuals. VirG is highly conserved among Shigella strains and appealing as a broad-spectrum vaccine candidate. In this study, we investigated the immunogenicity and protective capacity of VirG as a subunit vaccine in mice. The surface-exposed alpha (α) domain of VirG (VirGα) was produced as a recombinant protein. This region has almost identical immune reactivity to full-length VirG. Administered intramuscularly with alum, VirGα elicited robust immune responses and high protective efficacy against S. flexneri 2a and S. sonnei. Almost complete protection was afforded by VirGα given intranasally with the E. coli double mutant heat-labile toxin (dmLT). VirGα-specific antibodies recognized VirG expressed on live Shigella, and blocked Shigella adhesion and invasion to human colonic cells. These results show for the first time that VirGα is a promising cross-protective vaccine candidate to prevent Shigella infection.
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Affiliation(s)
- Girmay Desalegn
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Chitradevi S Tamilselvi
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Jose M Lemme-Dumit
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Shannon J Heine
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Dylan Dunn
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Esther Ndungo
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA
| | - Neeraj Kapoor
- Vaxcyte, Inc., 825 Industrial Road, San Carlos, CA, 94070, USA
| | - Edwin V Oaks
- Patuxent Research and Consulting Group, 3106 Arrowhead Farm Rd, Gambrills, MD, 21054, USA
| | - Jeff Fairman
- Vaxcyte, Inc., 825 Industrial Road, San Carlos, CA, 94070, USA
| | - Marcela F Pasetti
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685W. Baltimore Street, Baltimore, MD, 21201, USA.
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Turbyfill KR, Clarkson KA, Oaks EV, Zurawski DV, Vortherms AR, Kaminski RW. Development of the Shigella flexneri 2a, 3a, 6, and S. sonnei artificial Invaplex (Invaplex AR) vaccines. mSphere 2023; 8:e0007323. [PMID: 37389412 PMCID: PMC10449495 DOI: 10.1128/msphere.00073-23] [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: 02/13/2023] [Accepted: 05/16/2023] [Indexed: 07/01/2023] Open
Abstract
The Shigella artificial invasin complex (InvaplexAR) vaccine is a subunit approach that effectively induces robust immunogenicity directed to serotype-specific lipopolysaccharide and the broadly conserved IpaB and IpaC proteins. One advantage of the vaccine approach is the ability to adjust the constituents to address suboptimal immunogenicity and to change the Shigella serotype targeted by the vaccine. As the vaccine moves through the product development pipeline, substantial modifications have been made to address manufacturing feasibility, acceptability to regulatory authorities, and developing immunogenic and effective products for an expanded list of Shigella serotypes. Modifications of the recombinant clones used to express affinity tag-free proteins using well-established purification methods, changes to detergents utilized in the assembly process, and in vitro and in vivo evaluation of different Invaplex formulations have led to the establishment of a scalable, reproducible manufacturing process and enhanced immunogenicity of Invaplex products designed to protect against four of the most predominant Shigella serotypes responsible for global morbidity and mortality. These adjustments and improvements provide the pathway for the manufacture and clinical testing of a multivalent Invaplex vaccine. IMPORTANCE Shigella species are a major global health concern that cause severe diarrhea and dysentery in children and travelers to endemic areas of the world. Despite significant advancements in access to clean water, the increases in antimicrobial resistance and the risk of post-infection sequelae, including cognitive and physical stunting in children, highlight the urgent need for an efficacious vaccine. One promising vaccine approach, artificial Invaplex, delivers key antigens recognized by the immune system during infection, which results in increased resistance to re-infection. The work presented here describes novel modifications to a previously described vaccine approach resulting in improved methods for manufacturing and regulatory approvals, expansion of the breadth of coverage to all major Shigella serotypes, and an increase in the potency of artificial Invaplex.
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Affiliation(s)
- K. Ross Turbyfill
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Kristen A. Clarkson
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Edwin V. Oaks
- Patuxent Research and Consulting Group, Gambrills, Maryland, USA
| | - Daniel V. Zurawski
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Anthony R. Vortherms
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Robert W. Kaminski
- Department of Diarrheal Disease Research, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
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Cell-free protein synthesis systems for vaccine design and production. Curr Opin Biotechnol 2023; 79:102888. [PMID: 36641905 DOI: 10.1016/j.copbio.2022.102888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 12/14/2022] [Indexed: 01/15/2023]
Abstract
Vaccines are vital for protection against existing and emergent diseases. Current vaccine production strategies are limited by long production times, risky viral material, weak immunogenicity, and poor stability, ultimately restricting the safe or rapid production of vaccines for widespread utilization. Cell-free protein synthesis (CFPS) systems, which use extracted transcriptional and translational machinery from cells, are promising tools for vaccine production because they can rapidly produce proteins without the constraints of living cells, have a highly optimizable open system, and can be used for on-demand biomanufacturing. Here, we review how CFPS systems have been explored for the production of subunit, conjugate, virus-like particle (VLP), and membrane-augmented vaccines and as a tool in vaccine design. We also discuss efforts to address potential limitations with CFPS such as the presence of endotoxins, poor protein folding, reaction stability, and glycosylation to enable promising future vaccine design and production.
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Bautista L, Pill-Pepe L, Kapoor N, Snyder S, Chu E, Agarwal P, Sardar M, Arulkumar S, Berges A, Iverson M, Behrens C, Marcq O, Fairman J. Addition of Lauryldimethylamine N-Oxide (LDAO) to a Copper-Free Click Chemistry Reaction Improves the Conjugation Efficiency of a Cell-Free Generated CRM197 Variant to Clinically Important Streptococcus pneumoniae Serotypes. ACS OMEGA 2022; 7:34921-34928. [PMID: 36211053 PMCID: PMC9535640 DOI: 10.1021/acsomega.2c03481] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 09/07/2022] [Indexed: 05/22/2023]
Abstract
Strain-promoted azide-alkyne cycloaddition (SPAAC) reactions like click chemistry have the potential to be highly scalable, robust, and cost-effective methods for generating small- and large-molecule conjugates for a variety of applications. However, despite method improvements, the rates of copper-based click chemistry reactions continue to be much faster than the rates of copper-free click chemistry reactions, which makes broader deployment of click chemistry challenging from a safety and compatibility standpoint. In this study, we used a zwitterionic detergent, namely, lauryldimethylamine N-oxide (LDAO), in a copper-free click chemistry reaction to investigate its impact on the generation of conjugate vaccines (CVs). For this, we utilized an Xpress cell-free protein synthesis (CFPS) platform to generate a proprietary variant of CRM197 (eCRM) containing non-native amino acids (nnAA) with azide-containing side chains as a carrier protein for conjugation to several clinically relevant dibenzocyclooctyne (DBCO)-derivatized S. pneumoniae serotypes (types 3, 5, 18C, and 19A). For conjugation, we performed copper-free click chemistry in the presence and absence of LDAO. Our results show that the addition of LDAO significantly enhanced the reaction kinetics to generate larger conjugates, which were similarly immunogenic and equally stable to conjugates generated without LDAO. Most importantly, the addition of LDAO substantially improved the efficiency of the conjugation process. Thus, our results for the first time show that the addition of a zwitterionic surfactant to a copper-free click chemistry reaction can significantly accelerate the reaction kinetics along with improving the efficiency of the conjugation process.
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