Neisseria Heparin Binding Antigen is targeted by the human alternative pathway C3-convertase

Fede, Martina Di; Biagini, Massimiliano; Cartocci, Elena; Parillo, Carlo; Greco, Alessandra; Martinelli, Manuele; Marchi, Sara; Pezzicoli, Alfredo; Delany, Isabel; Paccani, Silvia Rossi

doi:10.1371/journal.pone.0194662

Cited by 4 publications

(4 citation statements)

References 30 publications

(52 reference statements)

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“…We have so far identified four proteases able to cleave NHBA in vitro , upstream or downstream of the Arg-rich region: the meningococcal NalP protease (upstream cleavage), that generates the C2 fragment containing the Arg-rich motif, hLf, C3-convertase and hK1 (downstream cleavage), three human proteases generating the C1 fragment, devoid of the Arg-rich domain. Both fragments are released from bacteria into the external milieu [15] [12] [27].…”

Section: Resultsmentioning

confidence: 99%

“…The Arg-rich region is highly conserved among different NHBA proteins and across MenB strains [12], suggesting a crucial role in NHBA function. However, there is yet no concrete explanation why, in the pharyngeal tract and bloodstream, four proteases are involved in NHBA processing, with meningococcal NalP targeting the Arg-rich region upstream, and kallikreins, C3-convertase [27] and lactoferrin [12] targeting it downstream. Bacterial colonization in the nasopharyngeal tract is the prerequisite for the N .…”

Section: Resultsmentioning

confidence: 99%

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NHBA is processed by kallikrein from human saliva

Pantano¹,

Marchi²,

Biagini³

et al. 2019

PLoS ONE

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Neisserial Heparin Binding Antigen (NHBA) is a surface-exposed lipoprotein of Neisseria meningitidis and a component of the Bexsero vaccine. NHBA is characterized by the presence of a highly conserved Arg-rich region involved in binding to heparin and heparan sulphate proteoglycans present on the surface of host epithelial cells, suggesting a possible role of NHBA during N . meningitidis colonization. NHBA has been shown to be cleaved by the meningococcal protease NalP and by human lactoferrin (hLF), a host protease presents in different body fluids (saliva, breast milk and serum). Cleavage occurs upstream or downstream the Arg-rich region. Since the human nasopharynx is the only known reservoir of infection, we further investigated the susceptibility of NHBA to human proteases present in the saliva to assess whether proteolytic cleavage could happen during the initial steps of colonization. Here we show that human saliva proteolytically cleaves NHBA, and identified human kallikrein 1 (hK1), a serine protease, as responsible for this cleavage. Kallikrein-related peptidases (KLKs) have a distinct domain structure and exist as a family of 15 genes which are differentially expressed in many tissues and in the central nervous system. They are present in plasma, lymph, urine, saliva, pancreatic juices, and other body fluids where they catalyze the proteolysis of several human proteins. Here we report the characterization of NHBA cleavage by the tissue kallikrein, expressed in saliva and the identification of the cleavage site on NHBA both, as recombinant protein or as native protein, when expressed on live bacteria. Overall, these findings provide new insights on NHBA as target of host proteases, highlights thepotential role of NHBA in the Neisseria meningitidis nasopharyngeal colonization, and of kallikrein as a defensive agent against meningococcal infection.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

NHBA is processed by kallikrein from human saliva

Pantano¹,

Marchi²,

Biagini³

et al. 2019

PLoS ONE

Self Cite

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“…The inhibition of the binding of NHBA and the α-peptide to DNA suggested that FCS affects the integrity of these proteins. Serum contains proteases, such as the C3 convertase of the alternative pathway and PKLK, which have previously been shown to cleave meningococcal NHBA [ 38 , 39 ]. However, these proteolyses should not affect the role of NHBA in biofilm formation as cleavage was shown to occur downstream of the arginine-rich region in this protein leaving an N-terminal fragment with DNA-binding capacity at the cell surface.…”

Section: Resultsmentioning

confidence: 99%

Serum proteases prevent bacterial biofilm formation: role of kallikrein and plasmin

et al. 2021

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Biofilm formation is a general strategy for bacterial pathogens to withstand host defense mechanisms. In this study, we found that serum proteases inhibit biofilm formation by Neisseria meningitidis, Neisseria gonorrhoeae, Haemophilus influenzae , and Bordetella pertussis . Confocal laser-scanning microscopy analysis revealed that these proteins reduce the biomass and alter the architecture of meningococcal biofilms. To understand the underlying mechanism, the serum was fractionated through size-exclusion chromatography and anion-exchange chromatography, and the composition of the fractions that retained anti-biofilm activity against N. meningitidis was analyzed by intensity-based absolute quantification mass spectrometry. Among the identified serum proteins, plasma kallikrein (PKLK), FXIIa, and plasmin were found to cleave neisserial heparin-binding antigen and the α-peptide of IgA protease on the meningococcal cell surface, resulting in the release of positively charged polypeptides implicated in biofilm formation by binding extracellular DNA. Further experiments also revealed that plasmin and PKLK inhibited biofilm formation of B. pertussis by cleaving filamentous hemagglutinin. We conclude that the proteolytic activity of serum proteases toward bacterial adhesins involved in biofilm formation could constitute a defense mechanism for the clearance of pathogens.

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“…On the basis of the sequence variability, over 400 different peptides have been described and the relationship between sequence variability and cross-protection remains to be defined The NHBA protein has an N-terminal region of approximately 250 residues predicted to be intrinsically disordered, and a highly conserved C-terminal domain (~180 residues), with an 8-stranded anti-parallel β-barrel folding (38, 39). NHBA undergoes proteolytic cleavage by meningococcal NalP protease and by eukaryotic proteases like human lactoferrin, Kallicrein, and the C3 convertase (42, 44).…”

Section: Formulating the Multicomponent Vaccine And Functional Characmentioning

confidence: 99%

The Development of a Vaccine Against Meningococcus B Using Reverse Vaccinology

Masignani¹,

Pizza²,

Moxon³

2019

Front. Immunol.

109

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The discovery of vaccine antigens through whole genome sequencing (WGS) contrasts with the classical hypothesis-driven laboratory-based analysis of microbes to identify components to elicit protective immunity. This radical change in scientific direction and action in vaccine research is captured in the term reverse vaccinology . The complete genome sequence of an isolate of Neisseria meningitidis serogroup B (MenB) was systematically analyzed to identify proteins predicted to be secreted or exported to the outer membrane. This identified hundreds of genes coding for potential surface-exposed antigens. These were amplified, cloned in expression vectors and used to immunize mice. Antisera against 350 recombinant antigens were obtained and analyzed in a panel of immunological assays from which 28 were selected as potentially protective based on the -antibody dependent, complement mediated- serum bactericidal activity assay. Testing of these candidate vaccine antigens, using a large globally representative strain collection of Neisseria species isolated from cases of disease and carriage, indicated that no single component would be sufficient to induce broad coverage and that a “universal” vaccine should contain multiple antigens. The final choice of antigens to be included was based on cross-protective ability, assayed by serum bactericidal activity and maximum coverage of the extensive antigenic variability of MenB strains. The resulting multivalent vaccine formulation selected consisted of three recombinant antigens (Neisserial Heparin Binding Antigen or NHBA, Factor H binding protein or fHbp and Neisseria Adhesin A or NadA). To improve immunogenicity and potential strain coverage, an outer membrane vesicle component obtained from the epidemic New Zealand strain (OMVNz) was added to the formulation to create a four component vaccine, called 4CMenB. A series of phase 2 and 3 clinical trials were conducted to evaluate safety and tolerability and to estimate the vaccine effectiveness of human immune responses at different ages and how these were affected by various factors including concomitant vaccine use and lot-to-lot consistency. 4CMenB was approved in Europe in 2013 and introduced in the National Immunization Program in the UK starting from September 2015 when the vaccine was offered to all newborns using a 2, 4, and 12 months schedule., The effectiveness against invasive MenB disease measured at 11 months after the study start and 5 months after the second vaccination was 83% and there have been no safety concerns.

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Neisseria Heparin Binding Antigen is targeted by the human alternative pathway C3-convertase

Cited by 4 publications

References 30 publications

NHBA is processed by kallikrein from human saliva

NHBA is processed by kallikrein from human saliva

Serum proteases prevent bacterial biofilm formation: role of kallikrein and plasmin

The Development of a Vaccine Against Meningococcus B Using Reverse Vaccinology

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