Bordetella pertussis Lipid A Recognition by Toll-like Receptor 4 and MD-2 Is Dependent on Distinct Charged and Uncharged Interfaces.

Lipid A in LPS activates innate immunity through the Toll-like receptor 4 (TLR4)-MD-2 complex on host cells. Variation in lipid A has significant consequences for TLR4 activation and thus may be a means by which Gram-negative bacteria modulate host immunity. However, although even minor changes in lipid A structure have been shown to affect downstream immune responses, the mechanism by which the TLR4-MD-2 receptor complex recognizes these changes is not well understood. We previously showed that strain BP338 of the human pathogen Bordetella pertussis, the causative agent of whooping cough, modifies its lipid A by the addition of glucosamine moieties that promote TLR4 activation in human, but not mouse, macrophages. Using site-directed mutagenesis and an NFκB reporter assay screen, we have identified several charged amino acid residues in TLR4 and MD-2 that are important for these species-specific responses; some of these are novel for responses to penta-acyl B. pertussis LPS, and their mutation does not affect the response to hexa-acylated Escherichia coli LPS or tetra-acylated lipid IVA. We additionally show evidence that suggests that recognition of penta-acylated B. pertussis lipid A is dependent on uncharged amino acids in TLR4 and MD-2 and that this is true for both human and mouse TLR4-MD-2 receptors. Taken together, we have demonstrated that the TLR4-MD-2 receptor complex recognizes variation in lipid A molecules using multiple sites for receptor-ligand interaction and propose that host-specific immunity to a particular Gram-negative bacterium is, at least in part, mediated by very subtle tuning of one of the earliest interactions at the host-pathogen interface.

Evaluation of a Province-Wide Type 1 Diabetes Care Plan for Children in the School Setting.

OBJECTIVES: The aim of this study was to identify perceptions of safety and effectiveness of a provincial type 1 diabetes school care plan, and to best inform future improvements in school care to accommodate the shifting needs of families, best clinical practices and new medical technologies. METHODS: A cross-sectional satisfaction and feedback questionnaire to inform quality improvement was offered to both families of children with type 1 diabetes who receive care at school through a Delegated Diabetes Care Plan and to their program coordinators during the 2017‒2018 school year. RESULTS: The response rate was 29.8% (160 of 537) for families and 68.2% (45 of 66) for coordinators. The majority of parents and coordinators reported that the care plan is meeting both safety and diabetes management needs. On a 7-point Likert scale, the safety score, expressed as mean (standard deviation), was 6.0 (1.2) by families and 5.7 (1.3) by coordinators, with higher scores reflecting greater satisfaction. Diabetes management was rated 5.6 (1.2) out of 7 by families, and 5.4 (0.8) out of 7 by coordinators. Families and coordinators expressed the need for individualization of care, and suggested modifications to how information is presented. There was near-unanimous support for future integration of continuous glucose-monitoring devices into the school setting. CONCLUSIONS: British Columbia's provision of diabetes care in the school setting is overall perceived to be safe and is generally well received by families and coordinators. In this study, we provide valuable information to improve the care of children with type 1 diabetes in schools, including support for further individualization of care and future integration of diabetes technology into the school setting.