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Neisseria meningitis remains a leading cause of sepsis and meningitis, and vaccines are required to prevent infections by this important human pathogen. Factor H binding protein (fHbp) is a key antigen that elicits protective immunity against the meningococcus and recruits the host complement regulator, fH. As the high affinity interaction between fHbp and fH could impair immune responses, we sought to identify non-functional fHbps that could act as effective immunogens. This was achieved by alanine substitution of fHbps from all three variant groups (V1, V2 and V3 fHbp) of the protein; while some residues affected fH binding in each variant group, the distribution of key amino underlying the interaction with fH differed between the V1, V2 and V3 proteins. The atomic structure of V3 fHbp in complex with fH and of the C-terminal barrel of V2 fHbp provide explanations to the differences in the precise nature of their interactions with fH, and the instability of the V2 protein. To develop transgenic models to assess the efficacy of non-functional fHbps, we determined the structural basis of the low level of interaction between fHbp and murine fH; in addition to changes in amino acids in the fHbp binding site, murine fH has a distinct conformation compared with the human protein that would sterically inhibit binding to fHbp. Non-functional V1 fHbps were further characterised by binding and structural studies, and shown in non-transgenic and transgenic mice (expressing chimeric fH that binds fHbp and precisely regulates complement system) to retain their immunogenicity. Our findings provide a catalogue of non-functional fHbps from all variant groups that can be included in new generation meningococcal vaccines, and establish proof-in-principle for clinical studies to compare their efficacy with wild-type fHbps.

<b><i>Background:</i></b> We tested a new, investigational robotic-assisted bronchoscope system with a remotely controlled catheter to access small peripheral bronchi with real-time driving under live visualization and distal tip articulation of the catheter. The unique catheter remains stationary once located at the biopsy position. <b><i>Objectives:</i></b> The primary objectives of this study were to evaluate the safety and feasibility of a new shape-sensing robotic bronchoscope system to bronchoscopically approach and facilitate the sampling of small peripheral pulmonary nodules of 1–3 cm. Secondary objectives included evaluating procedural characteristics and early performance trends associated with the use of the new robotic bronchoscope system. <b><i>Methods:</i></b> Subjects were enrolled according to study eligibility criteria at a single center. Navigation pathways were semi-automatically created using pre-procedure CT scans. Simultaneous (real-time) viewing of actual and virtual bronchi was used real time during navigation to the displayed target. An endobronchial ultrasound mini-probe was used to confirm lesion location. Flexible 19- to 23-G needles specifically designed to accommodate tight bend radii in transbronchial needle aspiration were used along with conventional biopsy tools. Enrolled subjects completed follow-up visits up to 6 months after the procedure. <b><i>Results:</i></b> The study included 29 subjects with a mean lesion size of 12.2 ± 4.2, 12.3 ± 3.3, and 11.7 ± 4.1 mm in the axial, coronal, and sagittal planes, respectively. The CT bronchus sign was absent in 41.4% of cases. In 96.6% of cases, the target was reached, and samples were obtained. No device-related adverse events and no instances of pneumothorax or excessive bleeding were observed during the procedure. Early performance trends demonstrated an overall diagnostic yield of 79.3% and a diagnostic yield for malignancy of 88%. <b><i>Conclusion:</i></b> This new robotic-assisted bronchoscope system safely navigated to very small peripheral airways under continuous visualization, and through maintenance of a static position, it provides a unique sampling capability for the biopsy of small solitary pulmonary nodules.

Neisseria meningitidis remains a leading cause of bacterial sepsis and meningitis. Complement is a key component of natural immunity against this important human pathogen, which has evolved multiple mechanisms to evade complement-mediated lysis. One approach adopted by the meningococcus is to recruit a human negative regulator of the complement system, factor H (fH), to its surface via a lipoprotein, factor H binding protein (fHbp). Additionally, fHbp is a key antigen in vaccines currently being evaluated in clinical trials. Here we characterize strains of N. meningitidis from several distinct clonal complexes which do not express fHbp; all strains were recovered from patients with disseminated meningococcal disease. We demonstrate that these strains have either a frameshift mutation in the fHbp open reading frame or have entirely lost fHbp and some flanking sequences. No fH binding was detected to other ligands among the fHbp-negative strains. The implications of these findings for meningococcal pathogenesis and prevention are discussed.

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