Prebiotics for people with cystic fibrosis.

BACKGROUND: Cystic fibrosis (CF) is a multisystem disease; the importance of growth and nutritional status is well established given their implications for lung function and overall survivability. Furthermore, it has been established that intestinal microbial imbalance and inflammation are present in people with CF. Oral prebiotics are commercially available substrates that are selectively utilised by host intestinal micro-organisms and may improve both intestinal and overall health. OBJECTIVES: To evaluate the benefits and harms of prebiotics for improving health outcomes in children and adults with CF. SEARCH METHODS: We searched the Cochrane Cystic Fibrosis Trials Register compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews. Date of last search: 19 October 2022. We also searched PubMed and online trials registries. Date of last search: 13 January 2023. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs assessing the efficacy of prebiotics in children and adults with CF. We planned to only include the first treatment period from cross-over RCTs, regardless of washout period. DATA COLLECTION AND ANALYSIS: We did not identify any relevant trials. MAIN RESULTS: We did not identify any relevant trials for inclusion in this review. AUTHORS' CONCLUSIONS: This review did not find any evidence for the use of prebiotics in people with CF. Until such evidence is available, it is reasonable for clinicians to follow any local guidelines and to discuss the use of dietary prebiotics with their patients. Large and robust RCTs assessing the dietary prebiotics of inulin or galacto-oligosaccharides or fructo-oligosaccharides, or any combination of these, are needed. Such studies should be of at least 12 months in duration and assess outcomes such as growth and nutrition, gastrointestinal symptoms, pulmonary exacerbations, lung function, inflammatory biomarkers, hospitalisations, intestinal microbial profiling, and faecal short-chain fatty acids. Trials should include both children and adults and aim to be adequately powered to allow for subgroup analysis by age.

Fractional exhaled nitric oxide in the assessment of exercise-induced bronchoconstriction: A multicenter retrospective analysis of UK-based athletes.

INTRODUCTION: Exercise-induced bronchoconstriction (EIB) is not only highly prevalent in people with asthma, but can also occur independently, particularly in athletes. Fractional exhaled nitric oxide (FeNO) is an indirect biomarker of type 2 airway inflammation that has an established role in the assessment and management of asthma. The aim was to evaluate the value of FeNO in the assessment of EIB in athletes. METHOD: Multicenter retrospective analysis. In total, 488 athletes (male: 76%) performed baseline FeNO, and spirometry pre- and post-indirect bronchial provocation via eucapnic voluntary hyperpnea (EVH). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for established FeNO thresholds-that is, intermediate (≥25 ppb) and high FeNO (≥40 ppb and ≥ 50 ppb)-and were evaluated against objective evidence of EIB (≥10% fall in FEV1 ). The diagnostic accuracy of FeNO was calculated using receiver operating characteristics area under the curve (ROC-AUC). RESULTS: Thirty-nine percent of the athletes had a post-EVH fall in FEV1 consistent with EIB. FeNO values ≥25 ppb, ≥40 ppb, and ≥ 50 ppb were observed in 42%, 23%, and 17% of the cohort, respectively. The sensitivity of FeNO ≥25 ppb was 55%, which decreased to 37% and 27% at ≥40 ppb and ≥ 50 ppb, respectively. The specificity of FeNO ≥25 ppb, ≥40 ppb, and ≥ 50 ppb was 66%, 86%, and 89%, respectively. The ROC-AUC for FeNO was 0.656. CONCLUSIONS: FeNO ≥40 ppb provides good specificity, that is, the ability to rule-in a diagnosis of EIB. However, due to the poor sensitivity and predictive values, FeNO should not be employed as a replacement for indirect bronchial provocation in athletes.

Distinguishing science from pseudoscience in commercial respiratory interventions: an evidence-based guide for health and exercise professionals.

Respiratory function has become a global health priority. Not only is chronic respiratory disease a leading cause of worldwide morbidity and mortality, but the COVID-19 pandemic has heightened attention on respiratory health and the means of enhancing it. Subsequently, and inevitably, the respiratory system has become a target of the multi-trillion-dollar health and wellness industry. Numerous commercial, respiratory-related interventions are now coupled to therapeutic and/or ergogenic claims that vary in their plausibility: from the reasonable to the absurd. Moreover, legitimate and illegitimate claims are often conflated in a wellness space that lacks regulation. The abundance of interventions, the range of potential therapeutic targets in the respiratory system, and the wealth of research that varies in quality, all confound the ability for health and exercise professionals to make informed risk-to-benefit assessments with their patients and clients. This review focuses on numerous commercial interventions that purport to improve respiratory health, including nasal dilators, nasal breathing, and systematized breathing interventions (such as pursed-lips breathing), respiratory muscle training, canned oxygen, nutritional supplements, and inhaled L-menthol. For each intervention we describe the premise, examine the plausibility, and systematically contrast commercial claims against the published literature. The overarching aim is to assist health and exercise professionals to distinguish science from pseudoscience and make pragmatic and safe risk-to-benefit decisions.

Annual risk of falls resulting in emergency department and hospital attendances for older people: an observational study of 781,081 individuals living in Wales (United Kingdom) including deprivation, frailty and dementia diagnoses between 2010 and 2020.

BACKGROUND: falls are common in older people, but associations between falls, dementia and frailty are relatively unknown. The impact of the COVID-19 pandemic on falls admissions has not been studied. AIM: to investigate the impact of dementia, frailty, deprivation, previous falls and the differences between years for falls resulting in an emergency department (ED) or hospital admission. STUDY DESIGN: longitudinal cross-sectional observational study. SETTING: older people (aged 65+) resident in Wales between 1 January 2010 and 31 December 2020. METHODS: we created a binary (yes/no) indicator for a fall resulting in an attendance to an ED, hospital or both, per person, per year. We analysed the outcomes using multilevel logistic and multinomial models. RESULTS: we analysed a total of 5,141,244 person years of data from 781,081 individuals. Fall admission rates were highest in 2012 (4.27%) and lowest in 2020 (4.27%). We found an increased odds ratio (OR [95% confidence interval]) of a fall admission for age (1.05 [1.05, 1.05] per year of age), people with dementia (2.03 [2.00, 2.06]) and people who had a previous fall (2.55 [2.51, 2.60]). Compared with fit individuals, those with frailty had ORs of 1.60 [1.58, 1.62], 2.24 [2.21, 2.28] and 2.94 [2.89, 3.00] for mild, moderate and severe frailty respectively. Reduced odds were observed for males (0.73 [0.73, 0.74]) and less deprived areas; most deprived compared with least OR 0.75 [0.74, 0.76]. CONCLUSIONS: falls prevention should be targeted to those at highest risk, and investigations into the reduction in admissions in 2020 is warranted.

Do home adaptation interventions help to reduce emergency fall admissions? A national longitudinal data-linkage study of 657,536 older adults living in Wales (UK) between 2010 and 2017.

BACKGROUND: falls are common in older people, but evidence for the effectiveness of preventative home adaptations is limited. AIM: determine whether a national home adaptation service, Care&Repair Cymru (C&RC), identified individuals at risk of falls occurring at home and reduced the likelihood of falls. STUDY DESIGN: retrospective longitudinal controlled non-randomised intervention cohort study. SETTING: our cohort consisted of 657,536 individuals aged 60+ living in Wales (UK) between 1 January 2010 and 31 December 2017. About 123,729 individuals received a home adaptation service. METHODS: we created a dataset with up to 41 quarterly observations per person. For each quarter, we observed if a fall occurred at home that resulted in either an emergency department or an emergency hospital admission. We analysed the data using multilevel logistic regression. RESULTS: compared to the control group, C&RC clients had higher odds of falling, with an odds ratio (OR [95% confidence interval]) of 1.93 [1.87, 2.00]. Falls odds was higher for females (1.44 [1.42, 1.46]), older age (1.07 [1.07, 1.07]), increased frailty (mild 1.57 [1.55, 1.60], moderate 2.31 [2.26, 2.35], severe 3.05 [2.96, 3.13]), and deprivation (most deprived compared to least: 1.16 [1.13, 1.19]). Client fall odds decreased post-intervention; OR 0.97 [0.96, 0.97] per quarter. Regional variation existed for falls (5.8%), with most variation at the individual level (31.3%). CONCLUSIONS: C&RC identified people more likely to have an emergency fall admission occurring at home, and their service reduced the odds of falling post-intervention. Service provisioning should meet the needs of an individual and need varies by personal and regional circumstance.

Asthma and obesity: endotoxin another insult to add to injury?

Low-grade inflammation is often an underlying cause of several chronic diseases such as asthma, obesity, cardiovascular disease, and type 2 diabetes mellitus (T2DM). Defining the mediators of such chronic low-grade inflammation often appears dependent on which disease is being investigated. However, downstream systemic inflammatory cytokine responses in these diseases often overlap, noting there is no doubt more than one factor at play to heighten the inflammatory response. Furthermore, it is increasingly believed that diet and an altered gut microbiota may play an important role in the pathology of such diverse diseases. More specifically, the inflammatory mediator endotoxin, which is a complex lipopolysaccharide (LPS) derived from the outer membrane cell wall of Gram-negative bacteria and is abundant within the gut microbiota, and may play a direct role alongside inhaled allergens in eliciting an inflammatory response in asthma. Endotoxin has immunogenic effects and is sufficiently microscopic to traverse the gut mucosa and enter the systemic circulation to act as a mediator of chronic low-grade inflammation in disease. Whilst the role of endotoxin has been considered in conditions of obesity, cardiovascular disease and T2DM, endotoxin as an inflammatory trigger in asthma is less well understood. This review has sought to examine the current evidence for the role of endotoxin in asthma, and whether the gut microbiota could be a dietary target to improve disease management. This may expand our understanding of endotoxin as a mediator of further low-grade inflammatory diseases, and how endotoxin may represent yet another insult to add to injury.

Do home modifications reduce care home admissions for older people? A matched control evaluation of the Care & Repair Cymru service in Wales.

BACKGROUND: home advice and modification interventions aim to promote independent living for those living in the community, but quantitative evidence of their effectiveness is limited. AIM: assess the risk of care home admissions for people with different frailty levels receiving home advice and modification interventions against a control group who do not. STUDY DESIGN AND SETTING: matched control evaluation using linked longitudinal data from the Secure Anonymised Information Linkage (SAIL) Databank, comprising people aged 60-95, registered with a SAIL contributing general practice. The intervention group received the Care & Repair Cymru (C & RC) service, a home advice and modification service available to residents in Wales. METHODS: frailty, age and gender were used in propensity score matching to assess the Hazard Ratio (HR) of care home admissions within a 1-, 3- and 5-year period for the intervention group (N = 93,863) compared to a matched control group (N = 93,863). Kaplan-Meier curves were used to investigate time to a care home admission. RESULTS: the intervention group had an increased risk of a care home admission at 1-, 3- and 5-years [HR (95%CI)] for those classified as fit [1-year: 2.02 (1.73, 2.36), 3-years: 1.87 (1.72, 2.04), 5-years: 1.99 (1.86, 2.13)] and mildly frail [1-year: 1.25 (1.09, 1.42), 3-years: 1.25 (1.17, 1.34), 5-years: 1.30 (1.23, 1.38)], but a reduced risk of care home admission for moderately [1-year: 0.66 (0.58, 0.75), 3-years: 0.75 (0.70, 0.80), 5-years: 0.83 (0.78, 0.88)] and severely frail individuals [1-year: 0.44 (0.37, 0.54), 3-years: 0.54 (0.49, 0.60), 5-years: 0.60(0.55, 0.66)]. CONCLUSIONS: HRs indicated that the C & RC service helped to prevent care home admissions for moderately and severely frail individuals. The HRs generally increased with follow-up duration.

Oral Fucoidan Attenuates Lung Pathology and Clinical Signs in a Severe Influenza a Mouse Model.

Fucoidans are known to be effective inhibitors of inflammation, and of virus binding and cellular entry. Undaria pinnatifida-derived fucoidan (UPF) was assessed in a severe influenza A (H1N1, PR8) infection model in mice. Initially, UPF was gavaged at 3.52 mg daily in a treatment model. Gross lung pathology (consolidation) was significantly reduced as compared to controls. UPF was then presented as a feed supplement at a rate of either nil, 3.52 mg/day or 7.04 mg/day in a prophylactic model, dosed three days before infection. A significant improvement was observed in the clinical signs of ill-health, as well as a reduction in gross lung pathology in animals treated with the higher dose, although there was no significant reduction in lung viral titres.

A Modular Vaccine Platform Combining Self-Assembled Peptide Cages and Immunogenic Peptides.

Subunit vaccines use delivery platforms to present minimal antigenic components for immunization. The benefits of such systems include multivalency, self-adjuvanting properties, and more specific immune responses. Previously, the design, synthesis, and characterization of self-assembling peptide cages (SAGEs) have been reported. In these, de novo peptides are combined to make hubs that assemble into nanoparticles when mixed in aqueous solution. Here it is shown that SAGEs are nontoxic particles with potential as accessible synthetic peptide scaffolds for the delivery of immunogenic components. To this end, SAGEs functionalized with the model antigenic peptides tetanus toxoid632-651 and ovalbumin323-339 drive antigen-specific responses both in vitro and in vivo, eliciting both CD4+ T cell and B cell responses. Additionally, SAGEs functionalized with the antigenic peptide hemagglutinin518-526 from the influenza virus are also able to drive a CD8+ T cell response in vivo. This work demonstrates the potential of SAGEs to act as a modular scaffold for antigen delivery, capable of inducing and boosting specific and tailored immune responses.

Mouse Platelet Ral GTPases Control P-Selectin Surface Expression, Regulating Platelet-Leukocyte Interaction.

OBJECTIVE: RalA and RalB GTPases are important regulators of cell growth, cancer metastasis, and granule secretion. The purpose of this study was to determine the role of Ral GTPases in platelets with the use of platelet-specific gene-knockout mouse models. APPROACH AND RESULTS: This study shows that platelets from double knockout mice, in which both GTPases have been deleted, show markedly diminished (≈85% reduction) P-selectin translocation to the surface membrane, suggesting a critical role in α-granule secretion. Surprisingly, however, there were only minor effects on stimulated release of soluble α- and δ-granule content, with no alteration in granule count, morphology, or content. In addition, their expression was not essential for platelet aggregation or thrombus formation. However, absence of surface P-selectin caused a marked reduction (≈70%) in platelet-leukocyte interactions in blood from RalAB double knockout mice, suggesting a role for platelet Rals in platelet-mediated inflammation. CONCLUSIONS: Platelet Ral GTPases primarily control P-selectin surface expression, in turn regulating platelet-leukocyte interaction. Ral GTPases could therefore be important novel targets for the selective control of platelet-mediated immune cell recruitment and inflammatory disease.

Selective Solid-Liquid and Liquid-Liquid Extraction of Lithium Chloride Using Strapped Calix[4]pyrroles.

LiCl is a classic "hard" ion salt that is present in lithium-rich brines and a key component in end-of-life materials (that is, used lithium-ion batteries). Its isolation and purification from like salts is a recognized challenge with potential strategic and economic implications. Herein, we describe two ditopic calix[4]pyrrole-based ion-pair receptors (2 and 3), that are capable of selectively capturing LiCl. Under solid-liquid extraction conditions, using 2 as the extractant, LiCl could be separated from a NaCl/KCl salt mixture containing as little as 1 % LiCl with circa 100 % selectivity, while receptor 3 achieved similar separations when the LiCl level was as low as 200 ppm. Under liquid-liquid extraction conditions using nitrobenzene as the non-aqueous phase, the extraction preference displayed by 2 is KCl>NaCl>LiCl. In contrast, 3 exhibits high selectivity towards LiCl over NaCl and KCl, with no appreciable extraction being observed for the latter two salts.

Comparable reductions in hyperpnoea-induced bronchoconstriction and markers of airway inflammation after supplementation with 6·2 and 3·1 g/d of long-chain n-3 PUFA in adults with asthma.

Although high dose n-3 PUFA supplementation reduces exercise- and hyperpnoea-induced bronchoconstriction (EIB/HIB), there are concurrent issues with cost, compliance and gastrointestinal discomfort. It is thus pertinent to establish the efficacy of lower n-3 PUFA doses. Eight male adults with asthma and HIB and eight controls without asthma were randomly supplemented with two n-3 PUFA doses (6·2 g/d (3·7 g EPA and 2·5 g DHA) and 3·1 g/d (1·8 g EPA and 1·3 g DHA)) and a placebo, each for 21 d followed by 14 d washout. A eucapnic voluntary hyperpnoea (EVH) challenge was performed before and after treatments. Outcome measures remained unchanged in the control group. In the HIB group, the peak fall in forced expiratory volume in 1 s (FEV1) after EVH at day 0 (-1005 (sd 520) ml, -30 (sd 18) %) was unchanged after placebo. The peak fall in FEV1 was similarly reduced from day 0 to day 21 of 6·2 g/d n-3 PUFA (-1000 (sd 460) ml, -29 (sd 17) % v. -690 (sd 460) ml, -20 (sd 15) %) and 3·1 g/d n-3 PUFA (-970 (sd 480) ml, -28 (sd 18) % v. -700 (sd 420) ml, -21 (sd 15) %) (P<0·001). Baseline fraction of exhaled nitric oxide was reduced by 24 % (P=0·020) and 31 % (P=0·018) after 6·2 and 3·1 g/d n-3 PUFA, respectively. Peak increases in 9α, 11ß PGF2 after EVH were reduced by 65 % (P=0·009) and 56 % (P=0·041) after 6·2 and 3·1 g/d n-3 PUFA, respectively. In conclusion, 3·1 g/d n-3 PUFA supplementation attenuated HIB and markers of airway inflammation to a similar extent as a higher dose. Lower doses of n-3 PUFA thus represent a potentially beneficial adjunct treatment for adults with asthma and EIB.

"Straining" to Separate the Rare Earths: How the Lanthanide Contraction Impacts Chelation by Diglycolamide Ligands.

The subtle energetic differences underpinning adjacent lanthanide discrimination are explored with diglycolamide ligands. Our approach converges liquid-liquid extraction experiments with solution-phase X-ray absorption spectroscopy (XAS) and density functional theory (DFT) simulations, spanning the lanthanide series. The homoleptic [(DGA)3Ln]3+ complex was confirmed in the organic extractive solution by XAS, and this was modeled using DFT. An interplay between steric strain and coordination energies apparently gives rise to a nonlinear trend in discriminatory lanthanide ion complexation across the series. Our results highlight the importance of optimizing chelate molecular geometry to account for both coordination interactions and strain energies when designing new ligands for efficient adjacent lanthanide separation for rare-earth refining.

Description of drug therapy problem resolution in a statewide care management program.

OBJECTIVE: To describe drug therapy problem (DTP) resolution as part of a statewide, team-based care management program. METHODS: This was a retrospective, observational study of DTPs documented between March 1 and August 31, 2015. Data were retrieved from a Web-based platform 5 months after the observation period. DTPs were placed into groups based on the credentials of the person who documented the DTP. Next, they were identified as being documented in a transitional or nontransitional care setting. DTPs were further classified into 1 of 3 categories: medication adherence, discrepancy, or optimization. Lastly, DTP resolution was assessed. Results were analyzed using descriptive statistics. RESULTS: During the 6-month study period, 135,100 DTPs were documented, with 99% (n = 133,847) being documented by social work care managers, nurse care managers, and pharmacy staff personnel. Pharmacy staff personnel documented the majority of DTPs (51.5%), and the majority of DTPs (55%) were identified in the transitional care setting. Nurse care managers resolved more discrepancy DTPs (59.3%), whereas pharmacy staff personnel resolved more optimization DTPs (47.2%). Social work care managers resolved more medication adherence DTPs (68.6%). CONCLUSIONS: Pharmacy staff personnel primarily identified and resolved opportunities to optimize medication use, whereas nurse care managers primarily identified and resolved medication discrepancies. Social work care managers primarily identified and resolved problems related to medication adherence. When each member of the interdisciplinary care team functioned at the top of their license, all types of DTPs were effectively identified and resolved.

CO2 Capture from Ambient Air by Crystallization with a Guanidine Sorbent.

Carbon capture and storage is an important strategy for stabilizing the increasing concentration of atmospheric CO2 and the global temperature. A possible approach toward reversing this trend and decreasing the atmospheric CO2 concentration is to remove the CO2 directly from air (direct air capture). Herein we report a simple aqueous guanidine sorbent that captures CO2 from ambient air and binds it as a crystalline carbonate salt by guanidinium hydrogen bonding. The resulting solid has very low aqueous solubility (Ksp =1.0(4)×10-8 ), which facilitates its separation from solution by filtration. The bound CO2 can be released by relatively mild heating of the crystals at 80-120 °C, which regenerates the guanidine sorbent quantitatively. Thus, this crystallization-based approach to CO2 separation from air requires minimal energy and chemical input, and offers the prospect for low-cost direct air capture technologies.

Aqueous Sulfate Separation by Sequestration of [(SO4 )2 (H2 O)4 ]4- Clusters within Highly Insoluble Imine-Linked Bis-Guanidinium Crystals.

Selective crystallization of sulfate with a simple bis-guanidinium ligand, self-assembled in situ from terephthalaldehyde and aminoguanidinium chloride, was employed as an effective way to separate the highly hydrophilic sulfate anion from aqueous solutions. The resulting bis-iminoguanidinium sulfate salt has exceptionally low aqueous solubility (Ksp =2.4×10-10 ), comparable to that of BaSO4 . Single-crystal X-ray diffraction analysis showed the sulfate anions are sequestered as [(SO4 )2 (H2 O)4 ]4- clusters within the crystals. Variable-temperature solubility measurements indicated the sulfate crystallization is slightly endothermic (ΔHcryst =3.7 kJ mol-1 ), thus entropy driven. The real-world utility of this crystallization-based approach for sulfate separation was demonstrated by removing up to 99 % of sulfate from seawater in a single step.

A prebiotic galactooligosaccharide mixture reduces severity of hyperpnoea-induced bronchoconstriction and markers of airway inflammation.

Gut microbes have a substantial influence on systemic immune function and allergic sensitisation. Manipulation of the gut microbiome through prebiotics may provide a potential strategy to influence the immunopathology of asthma. This study investigated the effects of prebiotic Bimuno-galactooligosaccharide (B-GOS) supplementation on hyperpnoea-induced bronchoconstriction (HIB), a surrogate for exercise-induced bronchoconstriction, and airway inflammation. A total of ten adults with asthma and HIB and eight controls without asthma were randomised to receive 5·5 g/d of either B-GOS or placebo for 3 weeks separated by a 2-week washout period. The peak fall in forced expiratory volume in 1 s (FEV1) following eucapnic voluntary hyperpnoea (EVH) defined HIB severity. Markers of airway inflammation were measured at baseline and after EVH. Pulmonary function remained unchanged in the control group. In the HIB group, the peak post-EVH fall in FEV1 at day 0 (-880 (sd 480) ml) was unchanged after placebo, but was attenuated by 40 % (-940 (sd 460) v. -570 (sd 310) ml, P=0·004) after B-GOS. In the HIB group, B-GOS reduced baseline chemokine CC ligand 17 (399 (sd 140) v. 323 (sd 144) pg/ml, P=0·005) and TNF-α (2·68 (sd 0·98) v. 2·18 (sd 0·59) pg/ml, P=0·040) and abolished the EVH-induced 29 % increase in TNF-α. Baseline C-reactive protein was reduced following B-GOS in HIB (2·46 (sd 1·14) v. 1·44 (sd 0·41) mg/l, P=0·015) and control (2·16 (sd 1·02) v. 1·47 (sd 0·33) mg/l, P=0·050) groups. Chemokine CC ligand 11 and fraction of exhaled nitric oxide remained unchanged. B-GOS supplementation attenuated airway hyper-responsiveness with concomitant reductions in markers of airway inflammation associated with HIB.

Polysaccharide-specific memory B cells generated by conjugate vaccines in humans conform to the CD27+IgG+ isotype-switched memory B Cell phenotype and require contact-dependent signals from bystander T cells activated by bacterial proteins to differentiate into plasma cells.

The polysaccharides (PS) surrounding encapsulated bacteria are generally unable to activate T cells and hence do not induce B cell memory (BMEM). PS conjugate vaccines recruit CD4(+) T cells via a carrier protein, such as tetanus toxoid (TT), resulting in the induction of PS-specific BMEM. However, the requirement for T cells in the subsequent activation of the BMEM at the time of bacterial encounter is poorly understood, despite having critical implications for protection. We demonstrate that the PS-specific BMEM induced in humans by a meningococcal serogroup C PS (Men C)-TT conjugate vaccine conform to the isotype-switched (IgG(+)CD27(+)) rather than the IgM memory (IgM(+)CD27(+)) phenotype. Both Men C and TT-specific BMEM require CD4(+) T cells to differentiate into plasma cells. However, noncognate bystander T cells provide such signals to PS-specific BMEM with comparable effect to the cognate T cells available to TT-specific BMEM. The interaction between the two populations is contact-dependent and is mediated in part through CD40. Meningococci drive the differentiation of the Men C-specific BMEM through the activation of bystander T cells by bacterial proteins, although these signals are enhanced by T cell-independent innate signals. An effect of the TT-specific T cells activated by the vaccine on unrelated BMEM in vivo is also demonstrated. These data highlight that any protection conferred by PS-specific BMEM at the time of bacterial encounter will depend on the effectiveness with which bacterial proteins are able to activate bystander T cells. Priming for T cell memory against bacterial proteins through their inclusion in vaccine preparations must continue to be pursued.

Human tonsil-derived dendritic cells are poor inducers of T cell immunity to mucosally encountered pathogens.

The mucosal immune system must initiate and regulate protective immunity, while balancing this immunity with tolerance to harmless antigens and bacterial commensals. We have explored the hypothesis that mucosal dendritic cells (DC) control the balance between regulation and immunity, by studying the responses of human tonsil-derived DC to Neisseria meningitidis as a model organism. We show that tonsil DC are able to sample their antigenic environment, internalizing Nm and expressing high levels of HLA-DR and CD86. However, in comparison to monocyte-derived DC (moDC), they respond to pathogen encounter with only low level cytokine production, largely dominated by TGFß. Functionally, tonsil DC also only stimulated low levels of antigen-specific T cell proliferation and cytokine production when compared to moDC. We therefore propose that the default role for DC in the nasopharynx is to maintain tolerance/ignorance of the large volume of harmless antigens and bacterial commensals encountered at the nasopharyngeal mucosa.