Fast-Spiking Interneurons Supply Feedforward Control of Bursting, Calcium, and Plasticity for Efficient Learning.

Fast-spiking interneurons (FSIs) are a prominent class of forebrain GABAergic cells implicated in two seemingly independent network functions: gain control and network plasticity. Little is known, however, about how these roles interact. Here, we use a combination of cell-type-specific ablation, optogenetics, electrophysiology, imaging, and behavior to describe a unified mechanism by which striatal FSIs control burst firing, calcium influx, and synaptic plasticity in neighboring medium spiny projection neurons (MSNs). In vivo silencing of FSIs increased bursting, calcium transients, and AMPA/NMDA ratios in MSNs. In a motor sequence task, FSI silencing increased the frequency of calcium transients but reduced the specificity with which transients aligned to individual task events. Consistent with this, ablation of FSIs disrupted the acquisition of striatum-dependent egocentric learning strategies. Together, our data support a model in which feedforward inhibition from FSIs temporally restricts MSN bursting and calcium-dependent synaptic plasticity to facilitate striatum-dependent sequence learning.

A Genetically Encoded Fluorescent Sensor Enables Rapid and Specific Detection of Dopamine in Flies, Fish, and Mice.

Dopamine (DA) is a central monoamine neurotransmitter involved in many physiological and pathological processes. A longstanding yet largely unmet goal is to measure DA changes reliably and specifically with high spatiotemporal precision, particularly in animals executing complex behaviors. Here, we report the development of genetically encoded GPCR-activation-based-DA (GRABDA) sensors that enable these measurements. In response to extracellular DA, GRABDA sensors exhibit large fluorescence increases (ΔF/F0 ∼90%) with subcellular resolution, subsecond kinetics, nanomolar to submicromolar affinities, and excellent molecular specificity. GRABDA sensors can resolve a single-electrical-stimulus-evoked DA release in mouse brain slices and detect endogenous DA release in living flies, fish, and mice. In freely behaving mice, GRABDA sensors readily report optogenetically elicited nigrostriatal DA release and depict dynamic mesoaccumbens DA signaling during Pavlovian conditioning or during sexual behaviors. Thus, GRABDA sensors enable spatiotemporally precise measurements of DA dynamics in a variety of model organisms while exhibiting complex behaviors.

Ca(V)1 and Ca(V)2 channels engage distinct modes of Ca(2+) signaling to control CREB-dependent gene expression.

Activity-dependent gene expression triggered by Ca(2+) entry into neurons is critical for learning and memory, but whether specific sources of Ca(2+) act distinctly or merely supply Ca(2+) to a common pool remains uncertain. Here, we report that both signaling modes coexist and pertain to Ca(V)1 and Ca(V)2 channels, respectively, coupling membrane depolarization to CREB phosphorylation and gene expression. Ca(V)1 channels are advantaged in their voltage-dependent gating and use nanodomain Ca(2+) to drive local CaMKII aggregation and trigger communication with the nucleus. In contrast, Ca(V)2 channels must elevate [Ca(2+)](i) microns away and promote CaMKII aggregation at Ca(V)1 channels. Consequently, Ca(V)2 channels are ~10-fold less effective in signaling to the nucleus than are Ca(V)1 channels for the same bulk [Ca(2+)](i) increase. Furthermore, Ca(V)2-mediated Ca(2+) rises are preferentially curbed by uptake into the endoplasmic reticulum and mitochondria. This source-biased buffering limits the spatial spread of Ca(2+), further attenuating Ca(V)2-mediated gene expression.

Reverse vaccinology-based identification of a novel surface lipoprotein that is an effective vaccine antigen against bovine infections caused by Pasteurella multocida.

Pasteurella multocida can infect a multitude of wild and domesticated animals, with infections in cattle resulting in hemorrhagic septicemia (HS) or contributing to bovine respiratory disease (BRD) complex. Current cattle vaccines against P. multocida consist of inactivated bacteria, which only offer limited and serogroup specific protection. Here, we describe a newly identified surface lipoprotein, PmSLP, that is present in nearly all annotated P. multocida strains isolated from cattle. Bovine associated variants span three of the four identified phylogenetic clusters, with PmSLP-1 and PmSLP-2 being restricted to BRD associated isolates and PmSLP-3 being restricted to isolates associated with HS. Recombinantly expressed, soluble PmSLP-1 (BRD-PmSLP) and PmSLP-3 (HS-PmSLP) vaccines were both able to provide full protection in a mouse sepsis model against the matched P. multocida strain, however no cross-protection and minimal serum IgG cross-reactivity was identified. Full protection against both challenge strains was achieved with a bivalent vaccine containing both BRD-PmSLP and HS-PmSLP, with serum IgG from immunized mice being highly reactive to both variants. Year-long stability studies with lyophilized antigen stored under various temperatures show no appreciable difference in biophysical properties or loss of efficacy in the mouse challenge model. PmSLP-1 and PmSLP-3 vaccines were each evaluated for immunogenicity in two independent cattle trials involving animals of different age ranges and breeds. In all four trials, vaccination with PmSLP resulted in an increase in antigen specific serum IgG over baseline. In a blinded cattle challenge study with a recently isolated HS strain, the matched HS-PmSLP vaccine showed strong efficacy (75-87.5% survival compared to 0% in the control group). Together, these data suggest that cattle vaccines composed of PmSLP antigens can be a practical and effective solution for preventing HS and BRD related P. multocida infections.

Identification of an Optimized Receptor-Binding Domain Subunit Vaccine against SARS-CoV-2.

Current vaccine efforts to combat SARS-CoV-2 are focused on the whole spike protein administered as mRNA, viral vector, or protein subunit. However, the SARS-CoV-2 receptor-binding domain (RBD) is the immunodominant portion of the spike protein, accounting for 90% of serum neutralizing activity. In this study, we constructed several versions of RBD and together with aluminum hydroxide or DDA (dimethyldioctadecylammonium bromide)/TDB (d-(+)-trehalose 6,6'-dibehenate) adjuvant evaluated immunogenicity in mice. We generated human angiotensin-converting enzyme 2 knock-in mice to evaluate vaccine efficacy in vivo following viral challenge. We found that 1) subdomain (SD)1 was essential for the RBD to elicit maximal immunogenicity; 2) RBDSD1 produced in mammalian HEK cells elicited better immunogenicity than did protein produced in insect or yeast cells; 3) RBDSD1 combined with the CD4 Th1 adjuvant DDA/TDB produced higher neutralizing Ab responses and stronger CD4 T cell responses than did aluminum hydroxide; 4) addition of monomeric human Fc receptor to RBDSD1 (RBDSD1Fc) significantly enhanced immunogenicity and neutralizing Ab titers; 5) the Beta version of RBDSD1Fc provided a broad range of cross-neutralization to multiple antigenic variants of concern, including Omicron; and 6) the Beta version of RBDSD1Fc with DDA/TDB provided complete protection against virus challenge in the knock-in mouse model. Thus, we have identified an optimized RBD-based subunit vaccine suitable for clinical trials.

Nunavimmi puvakkut kaggutimik aanniaqarniq: Qanuilirqitaa? Lung cancer in Nunavik: How are we doing? A retrospective matched cohort study.

BACKGROUND: Whether Inuit in Canada experience disparities in lung cancer survival remains unknown. When requiring investigation and treatment for lung cancer, all residents of Nunavik, the Inuit homeland in Quebec, are sent to the McGill University Health Centre (MUHC), in Montréal. We sought to compare survival among patients with lung cancer at the MUHC, who were residents of Nunavik and Montréal, Quebec, respectively. METHODS: We conducted a retrospective cohort study. Using lung cancer registry data, we identified Nunavik residents with histologically confirmed lung cancer diagnosed between 2005 and 2017. We aimed to match 2 Montréal residents to each Nunavik resident on sex, age, calendar year of diagnosis, and histology (non-small cell lung cancer v. small cell lung cancer). We reviewed medical records for data on additional patient characteristics and treatment, and obtained vital status from a provincial registry. We compared survival using Kaplan-Meier analysis and Cox proportional hazards regression. RESULTS: We included 95 residents of Nunavik and 185 residents of Montréal. For non-small cell lung cancer, median survival times were 321 (95% confidence interval [CI] 184-626) days for Nunavik (n = 71) and 720 (95% CI 536-1208) days for Montréal residents (n = 141). For small cell lung cancer, median survival times were 190 (95% CI 159-308) days for Nunavik (n = 24) and 270 (95% CI 194-766) days for Montréal residents (n = 44). Adjusting for matching variables, stage, performance status, and comorbidity, Nunavik residents had a higher hazard of death (hazard ratio 1.68, 95% CI 1.17-2.41). INTERPRETATION: Nunavik residents experience disparities in survival after lung cancer diagnosis. Although studies in other Inuit Nunangat regions are needed, our findings point to an urgent need to ensure that interventions aimed at improving lung cancer survival, including lung cancer screening, are accessible to Inuit Nunangat residents.

Correlated STORM-homoFRET imaging reveals highly heterogeneous membrane receptor structures.

Mapping the self-organization and spatial distribution of membrane proteins is key to understanding their function. Developing methods that can provide insight into correlations between membrane protein colocalization and interactions is challenging. We report here on a correlated stochastic optical reconstruction microscopy/homoFRET imaging approach for resolving the nanoscale distribution and oligomeric state of membrane proteins. Using live cell homoFRET imaging of carcinoembryonic antigen-related cellular adhesion molecule 1, a cell-surface receptor known to exist in a complex equilibrium between monomer and dimer/oligomer states, we revealed highly heterogeneous diffraction-limited structures on the surface of HeLa cells. Furthermore, correlated super-resolved stochastic optical reconstruction microscopy imaging showed that these structures comprised a complex mixture and spatial distribution of self-associated carcinoembryonic antigen-related cellular adhesion molecule 1 molecules. In conclusion, this correlated approach provides a compelling strategy for addressing challenging questions about the interplay between membrane protein concentration, distribution, interaction, clustering, and function.

Opposing roles of CLK SR kinases in controlling HIV-1 gene expression and latency.

BACKGROUND: The generation of over 69 spliced HIV-1 mRNAs from one primary transcript by alternative RNA splicing emphasizes the central role that RNA processing plays in HIV-1 replication. Control is mediated in part through the action of host SR proteins whose activity is regulated by multiple SR kinases (CLK1-4, SRPKs). METHODS: Both shRNA depletion and small molecule inhibitors of host SR kinases were used in T cell lines and primary cells to evaluate the role of these factors in the regulation of HIV-1 gene expression. Effects on virus expression were assessed using western blotting, RT-qPCR, and immunofluorescence. RESULTS: The studies demonstrate that SR kinases play distinct roles; depletion of CLK1 enhanced HIV-1 gene expression, reduction of CLK2 or SRPK1 suppressed it, whereas CLK3 depletion had a modest impact. The opposing effects of CLK1 vs. CLK2 depletion were due to action at distinct steps; reduction of CLK1 increased HIV-1 promoter activity while depletion of CLK2 affected steps after transcript initiation. Reduced CLK1 expression also enhanced the response to several latency reversing agents, in part, by increasing the frequency of responding cells, consistent with a role in regulating provirus latency. To determine whether small molecule modulation of SR kinase function could be used to control HIV-1 replication, we screened a GSK library of protein kinase inhibitors (PKIS) and identified several pyrazolo[1,5-b] pyridazine derivatives that suppress HIV-1 gene expression/replication with an EC50 ~ 50 nM. The compounds suppressed HIV-1 protein and viral RNA accumulation with minimal impact on cell viability, inhibiting CLK1 and CLK2 but not CLK3 function, thereby selectively altering the abundance of individual CLK and SR proteins in cells. CONCLUSIONS: These findings demonstrate the unique roles played by individual SR kinases in regulating HIV-1 gene expression, validating the targeting of these functions to either enhance latency reversal, essential for "Kick-and-Kill" strategies, or to silence HIV protein expression for "Block-and-Lock" strategies.

Identifying cellular factors that regulate HIV-1 RNA processing provides important insights into novel strategies to control this infection. Different members of the SR kinase family have distinct roles in regulating virus expression because they affect distinct steps of transcription/RNA processing. We identify inhibitors of these kinases that suppress HIV-1 gene expression and replication in multiple assay systems at nanomolar concentrations with limited or no cytotoxicity. Our results highlight the therapeutic potential of targeting the post-integration stage of the HIV-1 lifecycle to selectively enhance or reverse provirus latency. A greater understanding of the molecular mechanisms underlying the effects observed will facilitate the development of more targeted approaches to modulate HIV-1 latency on the path toward a "functional" cure for this infection.

Gonococcal Pelvic Inflammatory Disease: Placing Mechanistic Insights Into the Context of Clinical and Epidemiological Observations.

While infection by Neisseria gonorrhoeae is often asymptomatic in women, undetected infections can ascend into the upper genital tract to elicit an inflammatory response that manifests as pelvic inflammatory disease, with the outcomes depending on the intensity and duration of inflammation and whether it is localized to the endometrial, fallopian tube, ovarian, and/or other tissues. This review examines the contribution of N. gonorrhoeae versus other potential causes of pelvic inflammatory disease by considering new insights gained through molecular, immunological, and microbiome-based analyses, and the current epidemiological burden of infection, with an aim to highlighting key areas for future study.

Detection of SARS-CoV-2 Viral Particles Using Direct, Reagent-Free Electrochemical Sensing.

The development of new methods for direct viral detection using streamlined and ideally reagent-free assays is a timely and important, but challenging, problem. The challenge of combatting the COVID-19 pandemic has been exacerbated by the lack of rapid and effective methods to identify viral pathogens like SARS-CoV-2 on-demand. Existing gold standard nucleic acid-based approaches require enzymatic amplification to achieve clinically relevant levels of sensitivity and are not typically used outside of a laboratory setting. Here, we report reagent-free viral sensing that directly reads out the presence of viral particles in 5 minutes using only a sensor-modified electrode chip. The approach relies on a class of electrode-tethered sensors bearing an analyte-binding antibody displayed on a negatively charged DNA linker that also features a tethered redox probe. When a positive potential is applied, the sensor is transported to the electrode surface. Using chronoamperometry, the presence of viral particles and proteins can be detected as these species increase the hydrodynamic drag on the sensor. This report is the first virus-detecting assay that uses the kinetic response of a probe/virus complex to analyze the complexation state of the antibody. We demonstrate the performance of this sensing approach as a means to detect, within 5 min, the presence of the SARS-CoV-2 virus and its associated spike protein in test samples and in unprocessed patient saliva.

Neisseria gonorrhoeae infects the heterogeneous epithelia of the human cervix using distinct mechanisms.

Sexually transmitted infections are a critical public health issue. However, the mechanisms underlying sexually transmitted infections in women and the link between the infection mechanism and the wide range of clinical outcomes remain elusive due to a lack of research models mimicking human infection in vivo. We established a human cervical tissue explant model to mimic local Neisseria gonorrhoeae (GC) infections. We found that GC preferentially colonize the ectocervix by activating integrin-ß1, which inhibits epithelial shedding. GC selectively penetrate into the squamocolumnar junction (TZ) and endocervical epithelia by inducing ß-catenin phosphorylation, which leads to E-cadherin junction disassembly. Epithelial cells in various cervical regions differentially express carcinoembryonic antigen-related cell adhesion molecules (CEACAMs), the host receptor for GC opacity-associated proteins (OpaCEA). Relatively high levels were detected on the luminal membrane of ecto/endocervical epithelial cells but very low levels intracellularly in TZ epithelial cells. CEACAM-OpaCEA interaction increased ecto/endocervical colonization and reduced endocervical penetration by increasing integrin-ß1 activation and inhibiting ß-catenin phosphorylation respectively, through CEACAM downstream signaling. Thus, the intrinsic properties of cervical epithelial cells and phase-variation of bacterial surface molecules both play a role in controlling GC infection mechanisms and infectivity, preferential colonization or penetration, potentially leading to asymptomatic or symptomatic infection.

Holder pasteurization of donated human milk is effective in inactivating SARS-CoV-2.

BACKGROUND: Provision of pasteurized donor human milk, as a bridge to mother's own milk, is the standard of care for very low-birth-weight infants in hospital. The aim of this research was to confirm that Holder pasteurization (62.5°C for 30 min) would be sufficient to inactivate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in donated human milk samples. METHODS: We spiked frozen milk samples from 10 donors to the Rogers Hixon Ontario Human Milk Bank with SARS-CoV-2 to achieve a final concentration of 1 × 107 TCID50/mL (50% of the tissue culture infectivity dose per mL). We pasteurized samples using the Holder method or held them at room temperature for 30 minutes and plated serial dilutions on Vero E6 cells for 5 days. We included comparative controls in the study using milk samples from the same donors without addition of virus (pasteurized and unpasteurized) as well as replicates of Vero E6 cells directly inoculated with SARS-CoV-2. We reported cytopathic effects as TCID50/mL. RESULTS: We detected no cytopathic activity in any of the SARS-CoV-2-spiked milk samples that had been pasteurized using the Holder method. In the SARS-CoV-2-spiked milk samples that were not pasteurized but were kept at room temperature for 30 minutes, we observed a reduction in infectious viral titre of about 1 log. INTERPRETATION: Pasteurization of human milk by the Holder method (62.5°C for 30 min) inactivates SARS-CoV-2. Thus, in the event that donated human milk contains SARS-CoV-2 by transmission through the mammary gland or by contamination, this method of pasteurization renders milk safe for consumption and handling by care providers.

d-Glycero-ß-d-Manno-Heptose 1-Phosphate and d-Glycero-ß-d-Manno-Heptose 1,7-Biphosphate Are Both Innate Immune Agonists.

d-Glycero-ß-d-manno-heptose 1,7-biphosphate (ß-HBP) is a novel microbial-associated molecular pattern that triggers inflammation and thus has the potential to act as an immune modulator in many therapeutic contexts. To better understand the structure-activity relationship of this molecule, we chemically synthesized analogs of ß-HBP and tested their ability to induce canonical TIFA-dependent inflammation in human embryonic kidney cells (HEK 293T) and colonic epithelial cells (HCT 116). Of the analogs tested, only d-glycero-ß-d-manno-heptose 1-phosphate (ß-HMP) induced TIFA-dependent NF-κB activation and cytokine production in a manner similar to ß-HBP. This finding expands the spectrum of metabolites from the Gram-negative ADP-heptose biosynthesis pathway that can function as innate immune agonists and provides a more readily available agonist of the TIFA-dependent inflammatory pathway that can be easily produced by synthetic methods.

Bcl10 synergistically links CEACAM3 and TLR-dependent inflammatory signalling.

The neutrophil-specific innate immune receptor CEACAM3 functions as a decoy to capture Gram-negative pathogens, such as Neisseria gonorrhoeae, that exploit CEACAM family members to adhere to the epithelium. Bacterial binding to CEACAM3 results in their efficient engulfment and triggers activation of an nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-dependent inflammatory response by human neutrophils. Herein, we report that CEACAM3 cross-linking is not sufficient for induction of cytokine production and show that the inflammatory response induced by Neisseria gonorrhoeae infection is elicited by an integration of signals from CEACAM3 and toll-like receptors. Using neutrophils from a human CEACAM-expressing mouse line (CEABAC), we use a genetic approach to reveal a molecular bifurcation of the CEACAM3-mediated antimicrobial and inflammatory responses. Ex vivo experiments with CEABAC-Rac2-/- , CEABAC-Bcl10-/- , and CEABAC-Malt1-/- neutrophils indicate that these effectors are not necessary for gonococcal engulfment, yet all 3 effectors contribute to CEACAM3-mediated cytokine production. Interestingly, although Bcl10 and Malt1 are often inextricably linked, Bcl10 enabled synergy between toll-like receptor 4 and CEACAM3, whereas Malt1 did not. Together, these findings reveal an integration of the specific innate immune receptor CEACAM3 into the network of more conventional pattern recognition receptors, providing a mechanism by which the innate immune system can unleash its response to a relentless pathogen.

Oxytocin enhances hippocampal spike transmission by modulating fast-spiking interneurons.

Neuromodulatory control by oxytocin is essential to a wide range of social, parental and stress-related behaviours. Autism spectrum disorders (ASD) are associated with deficiencies in oxytocin levels and with genetic alterations of the oxytocin receptor (OXTR). Thirty years ago, Mühlethaler et al. found that oxytocin increases the firing of inhibitory hippocampal neurons, but it remains unclear how elevated inhibition could account for the ability of oxytocin to improve information processing in the brain. Here we describe in mammalian hippocampus a simple yet powerful mechanism by which oxytocin enhances cortical information transfer while simultaneously lowering background activity, thus greatly improving the signal-to-noise ratio. Increased fast-spiking interneuron activity not only suppresses spontaneous pyramidal cell firing, but also enhances the fidelity of spike transmission and sharpens spike timing. Use-dependent depression at the fast-spiking interneuron-pyramidal cell synapse is both necessary and sufficient for the enhanced spike throughput. We show the generality of this novel circuit mechanism by activation of fast-spiking interneurons with cholecystokinin or channelrhodopsin-2. This provides insight into how a diffusely delivered neuromodulator can improve the performance of neural circuitry that requires synapse specificity and millisecond precision.

Specific Binding to Differentially Expressed Human Carcinoembryonic Antigen-Related Cell Adhesion Molecules Determines the Outcome of Neisseria gonorrhoeae Infections along the Female Reproductive Tract.

The gonococcal Opa proteins are an antigenically variable family of surface adhesins that bind human carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), CEACAM3, CEACAM5, and/or CEACAM6, cell surface glycoproteins that are differentially expressed on a broad spectrum of human cells and tissues. While they are presumed to be important for infection, the significance of various Opa-CEACAM-mediated cellular interactions in the context of the genital tract has remained unclear. Here, we observed that CEACAM1 and CEACAM5 are differentially expressed on epithelia lining the upper and lower portions of the human female genital tract, respectively. Using transgenic mouse lines expressing human CEACAMs in a manner that reflects this differential pattern, we considered the impact of Opa-CEACAM interactions during uncomplicated lower genital tract infections versus during pelvic inflammatory disease. Our results demonstrate that Opa-CEACAM5 binding on vaginal epithelia facilitates the long-term colonization of the lower genital tract, while Opa protein binding to CEACAM1 on uterine epithelia enhances gonococcal association and penetration into these tissues. While these Opa-dependent interactions with CEACAM-expressing epithelial surfaces promote infection, Opa binding by neutrophil-expressed CEACAMs counterbalances this by facilitating more effective gonococcal clearance. Furthermore, during uterine infections, CEACAM-dependent tissue invasion aggravates disease pathology by increasing the acute inflammatory response. Together, these findings demonstrate that the outcome of infection is determined by both the cell type-specific expression of human CEACAMs and the CEACAM specificity of the Opa variants expressed, which combine to determine the level of gonococcal association with the genital mucosa versus the extent of CEACAM-dependent inflammation and gonococcal clearance by neutrophils.

Murine host response to Neisseria gonorrhoeae upper genital tract infection reveals a common transcriptional signature, plus distinct inflammatory responses that vary between reproductive cycle phases.

BACKGROUND: The emergence of fully antimicrobial resistant Neisseria gonorrhoeae has led global public health agencies to identify a critical need for next generation anti-gonococcal pharmaceuticals. The development and success of these compounds will rely upon valid pre-clinical models of gonorrhoeae infection. We recently developed and reported the first model of upper genital tract gonococcal infection. During initial characterization, we observed significant reproductive cycle-based variation in infection outcome. When uterine infection occurred in the diestrus phase, there was significantly greater pathology than during estrus phase. The aim of this study was to evaluate transcriptional profiles of infected uterine tissue from mice in either estrus or diestrus phase in order to elucidate possible mechanisms for these differences. RESULTS: Genes and biological pathways with phase-independent induction during infection showed a chemokine dominant cytokine response to Neisseria gonorrhoeae. Despite general induction being phase-independent, this common anti-gonococcal response demonstrated greater induction during diestrus phase infection. Greater activity of granulocyte adhesion and diapedesis regulators during diestrus infection, particularly in chemokines and diapedesis regulators, was also shown. In addition to a greater induction of the common anti-gonococcal response, Gene Set Enrichment Analysis identified a diestrus-specific induction of type-1 interferon signaling pathways. CONCLUSIONS: This transcriptional analysis of murine uterine gonococcal infection during distinct points in the natural reproductive cycle provided evidence for a common anti-gonococcal response characterized by significant induction of granulocyte chemokine expression and high proinflammatory mediators. The basic biology of this host response to N. gonorrhoeae in estrus and diestrus is similar at the pathway level but varies drastically in magnitude. Overlaying this, we observed type-1 interferon induction specifically in diestrus infection where greater pathology is observed. This supports recent work suggesting this pathway has a significant, possibly host-detrimental, function in gonococcal infection. Together these findings lay the groundwork for further examination of the role of interferons in gonococcal infection. Additionally, this work enables the implementation of the diestrus uterine infection model using the newly characterized host response as a marker of pathology and its prevention as a correlate of candidate vaccine efficacy and ability to protect against the devastating consequences of N. gonorrhoeae-associated sequelae.

Discordant Effects of Licensed Meningococcal Serogroup B Vaccination on Invasive Disease and Nasal Colonization in a Humanized Mouse Model.

Background: The multicomponent meningococcal serogroup B vaccine (4CMenB) is an outer membrane vesicle and recombinant protein-based vaccine licensed to protect against serogroup B meningococcal disease. It remains unknown whether this vaccine will prevent carriage or transmission, key aspects in long-term vaccine success and disease eradication. Methods: Using a "humanized" transgenic mouse model of nasal colonization, we took a systematic approach to estimate the potential for carriage prevention against antigenically diverse Neisseria meningitidis strains and to compare this protection to an invasive meningococcal disease challenge model. Results: The 4CMenB vaccine prevented morbidity and mortality after lethal invasive doses of all meningococcal strains tested. Immunization effectively prevented carriage with only 1 of 4 single antigen-matched strains but reduced or prevented nasal colonization by all 4 isolates with multiple cross-reacting antigens. Each immunized mouse had substantial immunoglobulin G targeting the challenge strains, indicating that antibody correlates with protection against sepsis but not nasal carriage. Conclusions: Immunization with the 4CMenB vaccine elicits a robust humoral response that correlates with protection against invasive challenge but not with prevention of asymptomatic colonization. This suggests that widespread use of this vaccine will reduce morbidity and mortality rates in immunized individuals, with the potential to contribute to herd protection against a subset of strains.

CEACAM1: contact-dependent control of immunity.

The carcinoembryonic-antigen-related cell-adhesion molecule (CEACAM) family of proteins has been implicated in various intercellular-adhesion and intracellular-signalling-mediated effects that govern the growth and differentiation of normal and cancerous cells. Recent studies show that there is an important role for members of the CEACAM family in modulating the immune responses associated with infection, inflammation and cancer. In this Review, we consider the evidence for CEACAM involvement in immunity, with a particular emphasis on CEACAM1, which functions as a regulatory co-receptor for both lymphoid and myeloid cell types.

Whole-Genome Sequencing Reveals the Origin and Rapid Evolution of an Emerging Outbreak Strain of Streptococcus pneumoniae 12F.

BACKGROUND: Streptococcus pneumoniaeis a major cause of community-acquired pneumonia and septicemia in adults. The global drug-susceptible capsular serotype 12F, clonal complex 218 caused several outbreaks in the United States between 1989 and 2008, as well as a recent large outbreak in Manitoba, Canada, that resulted in 36 cases of septicemia and 3 deaths. The evolutionary origin of the Canadian outbreak strain and its relationship to the historical US outbreak strains are not known. METHODS: Whole-genome deep sequencing was performed on isolates from the Canadian outbreak (n = 36), the US outbreaks (n = 9), and nonoutbreak surveys (n = 21). Phylogenomic analysis and comparative genomics were used to assess evolutionary relationships and to detect gene content differences between the isolates. RESULTS: The Canadian outbreak was closely related to sporadic cases that occurred preoutbreak in cross-border geographic regions in Manitoba, North Dakota, and Iowa. The emerging Canadian strain differed from US strains by acquisition of a cell-surface protein and macrolide resistance determinants via incorporation of a 5.3-kb mega cassette harboringmsrDandmefE Furthermore, during 11 months of transmission, this clone evolved rapidly and acquired fluoroquinolone resistance through precise stepwise mutations in bothparCandgyrA, and putative compensatory mutations inuraAorIMPDHunder drug selection. Alarmingly, this drug-resistant clone appears to have spread quickly to other regions of Canada and the United States, and replaced drug-susceptible strains. CONCLUSIONS: Whole-genome sequencing revealed an independent emergence and secondary adaptation of a new virulent and drug-resistant pneumococcal epidemic clone. Ongoing molecular surveillance is required, and measures to prevent its spread should be developed.