The Bexsero Neisseria meningitidis serogroup B vaccine antigen NHBA is a high-affinity chondroitin sulfate binding protein

Abstract

Neisseria meningitidis is a Gram-negative bacterial pathogen that causes life threatening meningitis and septicemia. Neisseria Heparin Binding Antigen (NHBA) is an outer membrane protein that binds heparin and heparan sulfate and DNA. This protein is one of the four antigens in the meningococcal serogroup B vaccine Bexsero. In the current study, we sought to define the full glycan-binding repertoire of NHBA to better understand its role in meningococcal pathogenesis and vaccine efficacy. Glycan array analysis revealed binding to 28 structures by recombinant NHBA. Surface plasmon resonance was used to confirm the binding phenotype and to determine the affinity of the interactions. These studies revealed that the highest affinity binding of NHBA was with chondroitin sulfate (KD = 5.2 nM). This affinity is 10-fold higher than observed for heparin. Analysis of binding with well-defined disaccharides of the different chondroitin sulfate types demonstrated that the most preferred ligand has a sulfate at the 2 position of the GlcA/IdoA and 6 position of the GalNAc, which is an equivalent structure to chondroitin sulfate D. Chondroitin sulfate is widely expressed in human tissues, while chondroitin sulfate D is predominantly expressed in the brain and may constitute a new receptor structure for meningococci.

The novel E. coli cell division protein, YtfB, plays a role in eukaryotic cell adhesion

“…Interestingly, UTI89ΔytfB cells bound to more glycans (103) compared to UTI89 cells (85), and 39 of these were bound by both strains ( Supplementary Table 1). This increase in glycan binding of the UTI89ΔytfB mutant may be because some surface structures that bind glycans are masked by the presence of YtfB, a phenomenon which has also been observed in Neisseria meningitidis 29 . There were two specific glycans which only showed binding by both wild type cells and recombinant YtfB protein, but not the UTI89ΔytfB mutant, providing strong evidence of specific binding of these glycans by YtfB.…”

The Neisseria gonorrhoeae Vaccine Candidate NHBA Elicits Antibodies That Are Bactericidal, Opsonophagocytic and That Reduce Gonococcal Adherence to Epithelial Cells

“…The phylogenetic relatedness of these NHBA variants is shown in Figure 1 c, and a panel of strains representative of NHBA diversity were used in subsequent assays. Given the sequence conservation of the C-terminal ( Figure 1 b), that the structure of the meningococcal NHBA C-terminal region has been characterized [ 15 , 18 , 19 ] and that the C-terminal region is more likely to be exposed and accessible to vaccine induced antibodies, we focused our subsequent investigation on both the recombinant full length NHBA and a C-terminal NHBA fragment (NHBA-c) ( Figure 1 a).…”

“…The N. meningitidis NHBA (previously called GNA2132) is a component of 4CMenB, present as a NHBA-GNA1030 fusion protein [13]. The meningococcal NHBA (NHBA Nm ) is a surface-exposed lipoprotein, that consists of three regions: an N-terminal region (up to residues 200-250) that is predicted to be intrinsically disordered and unfolded [14]; a central arginine-rich region that binds glycans including heparin, heparin sulfate and chondroitin sulfate [15][16][17], and a C-terminal region that folds as an anti-parallel β-barrel [14,18,19]. NHBA Nm is relatively well conserved, although the N-terminal region contains several insertions/deletions between different meningococcal strains [14].…”

Investigation of Whole Cell Meningococcal Glycan Interactions Using High Throughput Glycobiology Techniques: Glycan Array and Surface Plasmon Resonance

“…Insert a regeneration step in the sample overview, and remove the carry-over control. 6. Analyse using the BIAcore evaluation software.…”

“…In prior studies, we used glycan array analysis as a screening tool to characterise the glycointeractome of the Neisseria meningitidis serogroup B strain MC58 (5). Glycan array analysis of the wild type MC58 strain allowed us to determine the glycan binding properties of the organism, and by comparison the binding properties of mutant strains lacking major outer membrane structures, we determined the meningococcal surface structures potentially responsible for mediating the interactions (5,6). This approach can be applied to similar investigations of other meningococcal serogroups and mutant strains.…”