A novel interaction between factor H SCR 6 and the meningococcal vaccine candidate GNA1870: Implications for meningococcal pathogenesis and vaccine development

ABSTRACT Factor H-binding protein (fHbp) is a novel meningococcal vaccine candidate that elicits serum antibodies that activate classical complement pathway bacteriolysis and also inhibit binding of the complement down-regulatory protein, factor H, to the bacterial surface. One limitation of fHbp as a vaccine candidate is antigenic variability, since antibodies to fHbp in the variant 1 (v.1) antigenic group do not protect against strains expressing v.2 or v.3 proteins, and vice versa. We have identified amino acid residues of epitopes recognized by bactericidal anti-fHbp monoclonal antibodies prepared against fHbp from each of the variant groups. One epitope expressed by nearly all v.1 proteins mapped to the B domain, while epitopes expressed by fHbp v.2 or v.3 mapped to the C domain. The results provided the rationale for engineering chimeric fHbp molecules containing the A domain (which is conserved across all variant groups), a portion of the B domain of a v.1 protein, and the carboxyl-terminal portion of the B domain and the C domain of a v.2 protein. By enzyme-linked immunosorbent assay, the resulting recombinant chimeric proteins expressed epitopes from all three variant groups. In mice, the chimeric vaccines elicited serum antibodies with bactericidal activity against a panel of genetically diverse strains expressing fHbp v.1, v.2, or v.3. The data demonstrate the feasibility of preparing a meningococcal vaccine from a single recombinant protein that elicits broad bactericidal activity, including group B strains, which account for 50 percent of cases of meningococcal disease and for which there currently is no broadly protective vaccine.

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The Meningococcal Vaccine Candidate Neisserial Surface Protein A (NspA) Binds to Factor H and Enhances Meningococcal Resistance to Complement

PLoS Pathogens ◽

10.1371/journal.ppat.1001027 ◽

2010 ◽

Vol 6 (7) ◽

pp. e1001027 ◽

Cited By ~ 112

Author(s):

Lisa A. Lewis ◽

Jutamas Ngampasutadol ◽

Ruth Wallace ◽

Jane E. A. Reid ◽

Ulrich Vogel ◽

...

Keyword(s):

Vaccine Candidate ◽

Protein A ◽

Surface Protein ◽

Factor H ◽

Meningococcal Vaccine

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The Meningococcal Vaccine Candidate GNA1870 Binds the Complement Regulatory Protein Factor H and Enhances Serum Resistance

The Journal of Immunology ◽

10.4049/jimmunol.177.1.501 ◽

2006 ◽

Vol 177 (1) ◽

pp. 501-510 ◽

Cited By ~ 303

Author(s):

Guillermo Madico ◽

Jo Anne Welsch ◽

Lisa A. Lewis ◽

Anne McNaughton ◽

David H. Perlman ◽

...

Keyword(s):

Vaccine Candidate ◽

Regulatory Protein ◽

Factor H ◽

Serum Resistance ◽

Meningococcal Vaccine ◽

Complement Regulatory Protein ◽

Protein Factor

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Engineering a Live Attenuated Porcine Epidemic Diarrhea Virus Vaccine Candidate via Inactivation of the Viral 2'-O-Methyltransferase and the Endocytosis Signal of the Spike Protein

Journal of Virology ◽

10.1128/jvi.00406-19 ◽

2019 ◽

Vol 93 (15) ◽

Cited By ~ 10

Author(s):

Yixuan Hou ◽

Hanzhong Ke ◽

Jineui Kim ◽

Dongwan Yoo ◽

Yunfang Su ◽

...

Keyword(s):

Porcine Epidemic Diarrhea Virus ◽

Vaccine Development ◽

Vaccine Candidate ◽

Spike Protein ◽

Economic Losses ◽

High Dose ◽

Type I ◽

Viral Pathogen ◽

Diarrhea Virus ◽

Porcine Epidemic Diarrhea

ABSTRACT Porcine epidemic diarrhea virus (PEDV) causes high mortality in neonatal piglets; however, effective and safe vaccines are still not available. We hypothesized that inactivation of the 2′-O-methyltransferase (2′-O-MTase) activity of nsp16 and the endocytosis signal of the spike protein attenuates PEDV yet retains its immunogenicity in pigs. We generated a recombinant PEDV, KDKE4A, with quadruple alanine substitutions in the catalytic tetrad of the 2′-O-MTase using a virulent infectious cDNA clone, icPC22A, as the backbone. Next, we constructed another mutant, KDKE4A-SYA, by abolishing the endocytosis signal of the spike protein of KDKE4A. Compared with icPC22A, the KDKE4A and KDKE4A-SYA mutants replicated less efficiently in vitro but induced stronger type I and type III interferon responses. The pathogenesis and immunogenicities of the mutants were evaluated in gnotobiotic piglets. The virulence of KDKE4A-SYA and KDKE4A was significantly reduced compared with that of icPC22A. Mortality rates were 100%, 17%, and 0% in the icPC22A-, KDKE4A-, and KDKE4A-SYA-inoculated groups, respectively. At 21 days postinoculation (dpi), all surviving pigs were challenged orally with a high dose of icPC22A. The KDKE4A-SYA- and KDKE4A-inoculated pigs were protected from the challenge, because no KDKE4A-SYA- and one KDKE4A-inoculated pig developed diarrhea whereas all the pigs in the mock-inoculated group had severe diarrhea, and 33% of them died. Furthermore, we serially passaged the KDKE4A-SYA mutant in pigs three times and did not find any reversion of the introduced mutations. The data suggest that KDKE4A-SYA may be a PEDV vaccine candidate. IMPORTANCE PEDV is the most economically important porcine enteric viral pathogen and has caused immense economic losses in the pork industries in many countries. Effective and safe vaccines are desperately required but still not available. 2′-O-MTase (nsp16) is highly conserved among coronaviruses (CoVs), and the inactivation of nsp16 in live attenuated vaccines has been attempted for several betacoronaviruses. We show that inactivation of both 2′-O-MTase and the endocytosis signal of the spike protein is an approach to designing a promising live attenuated vaccine for PEDV. The in vivo passaging data also validated the stability of the KDKE4A-SYA mutant. KDKE4A-SYA warrants further evaluation in sows and their piglets and may be used as a platform for further optimization. Our findings further confirmed that nsp16 can be a universal target for CoV vaccine development and will aid in the development of vaccines against other emerging CoVs.

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Attenuated Replication of Lassa Virus Vaccine Candidate ML29 in STAT-1-/- Mice

Pathogens ◽

10.3390/pathogens8010009 ◽

2019 ◽

Vol 8 (1) ◽

pp. 9 ◽

Cited By ~ 5

Author(s):

Dylan Johnson ◽

Jenny Jokinen ◽

Igor Lukashevich

Keyword(s):

Vaccine Development ◽

Vaccine Candidate ◽

Small Animal ◽

Vero Cells ◽

Lassa Fever ◽

Effective Vaccine ◽

Cell Mediated Immunity ◽

Lassa Virus ◽

Cell Responses ◽

Fold Reduction

Lassa virus (LASV), a highly prevalent mammalian arenavirus endemic in West Africa, can cause Lassa fever (LF), which is responsible for thousands of deaths annually. LASV is transmitted to humans from naturally infected rodents. At present, there is not an effective vaccine nor treatment. The genetic diversity of LASV is the greatest challenge for vaccine development. The reassortant ML29 carrying the L segment from the nonpathogenic Mopeia virus (MOPV) and the S segment from LASV is a vaccine candidate under current development. ML29 demonstrated complete protection in validated animal models against a Nigerian strain from clade II, which was responsible for the worst outbreak on record in 2018. This study demonstrated that ML29 was more attenuated than MOPV in STAT1-/- mice, a small animal model of human LF and its sequelae. ML29 infection of these mice resulted in more than a thousand-fold reduction in viremia and viral load in tissues and strong LASV-specific adaptive T cell responses compared to MOPV-infected mice. Persistent infection of Vero cells with ML29 resulted in generation of interfering particles (IPs), which strongly interfered with the replication of LASV, MOPV and LCMV, the prototype of the Arenaviridae. ML29 IPs induced potent cell-mediated immunity and were fully attenuated in STAT1-/- mice. Formulation of ML29 with IPs will improve the breadth of the host’s immune responses and further contribute to development of a pan-LASV vaccine with full coverage meeting the WHO requirements.

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Identification of lipid A deacylase as a novel, highly conserved and protective antigen against enterohemorrhagic Escherichia coli

Scientific Reports ◽

10.1038/s41598-019-53197-z ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Maricarmen Rojas-Lopez ◽

Manuele Martinelli ◽

Valentina Brandi ◽

Grégory Jubelin ◽

Fabio Polticelli ◽

...

Keyword(s):

Lipid A ◽

Vaccine Development ◽

Protective Antigen ◽

Vaccine Candidate ◽

Bacterial Load ◽

Enterohemorrhagic Escherichia Coli ◽

Protein Antigens ◽

E Coli ◽

Epidemiology Data ◽

Potential Vaccine

AbstractEnterohemorrhagic E. coli (EHEC) is a major cause of large outbreaks worldwide associated with hemorrhagic colitis and hemolytic uremic syndrome. While vaccine development is warranted, a licensed vaccine, specific for human use, against EHEC is not yet available. In this study, the reverse vaccinology approach combined with genomic, transcriptional and molecular epidemiology data was applied on the EHEC O157:H7 genome to select new potential vaccine candidates. Twenty-four potential protein antigens were identified and one of them (MC001) was successfully expressed onto Generalized Modules for Membrane Antigens (GMMA) delivery system. GMMA expressing this vaccine candidate was immunogenic, raising a specific antibody response. Immunization with the MC001 candidate was able to reduce the bacterial load of EHEC O157:H7 strain in feces, colon and caecum tissues after murine infection. MC001 is homologue to lipid A deacylase enzyme (LpxR), and to our knowledge, this is the first study describing it as a potential vaccine candidate. Gene distribution and sequence variability analysis showed that MC001 is present and conserved in EHEC and in enteropathogenic E. coli (EPEC) strains. Given the high genetic variability among and within E. coli pathotypes, the identification of such conserved antigen suggests that its inclusion in a vaccine might represent a solution against major intestinal pathogenic strains.

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Characterization of the Immune Response of MERS-CoV Vaccine Candidates Derived from Two Different Vectors in Mice

Viruses ◽

10.3390/v12010125 ◽

2020 ◽

Vol 12 (1) ◽

pp. 125 ◽

Cited By ~ 7

Author(s):

Entao Li ◽

Feihu Yan ◽

Pei Huang ◽

Hang Chi ◽

Shengnan Xu ◽

...

Keyword(s):

Immune Responses ◽

Antibody Response ◽

Rabies Virus ◽

Vaccine Development ◽

Vaccine Candidate ◽

Viral Vector ◽

Vaccine Vector ◽

Vaccine Candidates ◽

Cellular Immune Responses ◽

Cellular Immune

Middle East respiratory syndrome (MERS) is an acute, high-mortality-rate, severe infectious disease caused by an emerging MERS coronavirus (MERS-CoV) that causes severe respiratory diseases. The continuous spread and great pandemic potential of MERS-CoV make it necessarily important to develop effective vaccines. We previously demonstrated that the application of Gram-positive enhancer matrix (GEM) particles as a bacterial vector displaying the MERS-CoV receptor-binding domain (RBD) is a very promising MERS vaccine candidate that is capable of producing potential neutralization antibodies. We have also used the rabies virus (RV) as a viral vector to design a recombinant vaccine by expressing the MERS-CoV S1 (spike) protein on the surface of the RV. In this study, we compared the immunological efficacy of the vaccine candidates in BALB/c mice in terms of the levels of humoral and cellular immune responses. The results show that the rabies virus vector-based vaccine can induce remarkably earlier antibody response and higher levels of cellular immunity than the GEM particles vector. However, the GEM particles vector-based vaccine candidate can induce remarkably higher antibody response, even at a very low dose of 1 µg. These results indicate that vaccines constructed using different vaccine vector platforms for the same pathogen have different rates and trends in humoral and cellular immune responses in the same animal model. This discovery not only provides more alternative vaccine development platforms for MERS-CoV vaccine development, but also provides a theoretical basis for our future selection of vaccine vector platforms for other specific pathogens.

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Role of Factor H Binding Protein in Neisseria meningitidis Virulence and Its Potential as a Vaccine Candidate To Broadly Protect against Meningococcal Disease

Microbiology and Molecular Biology Reviews ◽

10.1128/mmbr.00056-12 ◽

2013 ◽

Vol 77 (2) ◽

pp. 234-252 ◽

Cited By ~ 68

Author(s):

L. K. McNeil ◽

R. J. Zagursky ◽

S. L. Lin ◽

E. Murphy ◽

G. W. Zlotnick ◽

...

Keyword(s):

Neisseria Meningitidis ◽

Meningococcal Disease ◽

Vaccine Candidate ◽

Binding Protein ◽

Factor H

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Differential Activation of Human and Mouse Toll-Like Receptor 4 by the Adjuvant Candidate LpxL1 of Neisseria meningitidis

Infection and Immunity ◽

10.1128/iai.00005-08 ◽

2008 ◽

Vol 76 (8) ◽

pp. 3801-3807 ◽

Cited By ~ 56

Author(s):

Liana Steeghs ◽

A. Marijke Keestra ◽

Andries van Mourik ◽

Heli Uronen-Hansson ◽

Peter van der Ley ◽

...

Keyword(s):

Neisseria Meningitidis ◽

Lipid A ◽

Vaccine Development ◽

Meningococcal Vaccine ◽

Toll Like Receptor ◽

Wild Type ◽

Toll Like Receptor 4 ◽

Species Specific ◽

Human And Mouse ◽

Dc Maturation

ABSTRACT Neisseria meningitidis LpxL1 lipopolysaccharide (LPS) bearing penta-acylated lipid A is considered a promising adjuvant candidate for inclusion in future N. meningitidis vaccines, as it elicits a markedly reduced endotoxic response in human macrophages relative to that in wild-type (hexa-acylated) LPS, while it is an equally effective adjuvant in mice. As dendritic cells (DC) and Toll-like receptors (TLR) are regarded as central mediators in the initiation of an immune response, here we evaluated the ability of LpxL1 LPS to mature and to activate human DC and examined its TLR4-/MD-2-activating properties. Unexpectedly, purified LpxL1 LPS displayed minimal human DC-stimulating properties compared to wild-type LPS. Although whole bacteria induced DC maturation and activation irrespective of their type of LPS, the LpxL1 mutant failed to activate the human recombinant TLR4/MD-2 complex expressed in HeLa cells. Similarly, purified LpxL1 LPS was unable to activate human TLR4/MD-2 and it even acted as an antagonist of wild-type LPS. Both wild-type and LpxL1 LPSs activated the murine TLR4/MD-2 complex, consistent with their abilities to induce maturation and activation of murine DC. Assays with cells transfected with different combinations of human and murine TLR4 and MD-2 indicated that TLR4 was a more-major determinant of the LPS response than MD-2. The species-specific activation of the TLR4/MD-2 complex by LpxL1 LPS may have an impact on the use of LpxL1 LPS as an adjuvant and the use of murine immunization models in human meningococcal vaccine development.

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