A pan-influenza antibody inhibiting neuraminidase via receptor mimicry.

Rapidly evolving influenza A viruses (IAVs) and influenza B viruses (IBVs) are major causes of recurrent lower respiratory tract infections. Current influenza vaccines elicit antibodies predominantly to the highly variable head region of haemagglutinin and their effectiveness is limited by viral drift1 and suboptimal immune responses2. Here we describe a neuraminidase-targeting monoclonal antibody, FNI9, that potently inhibits the enzymatic activity of all group 1 and group 2 IAVs, as well as Victoria/2/87-like, Yamagata/16/88-like and ancestral IBVs. FNI9 broadly neutralizes seasonal IAVs and IBVs, including the immune-evading H3N2 strains bearing an N-glycan at position 245, and shows synergistic activity when combined with anti-haemagglutinin stem-directed antibodies. Structural analysis reveals that D107 in the FNI9 heavy chain complementarity-determinant region 3 mimics the interaction of the sialic acid carboxyl group with the three highly conserved arginine residues (R118, R292 and R371) of the neuraminidase catalytic site. FNI9 demonstrates potent prophylactic activity against lethal IAV and IBV infections in mice. The unprecedented breadth and potency of the FNI9 monoclonal antibody supports its development for the prevention of influenza illness by seasonal and pandemic viruses.

Uric acid-driven Th17 differentiation requires inflammasome-derived IL-1 and IL-18.

Uric acid is released from damaged cells and serves as a danger signal that alerts the immune system to potential threats, even in the absence of microbial infection. Uric acid modulation of innate immune responses has been extensively studied, but the impact of this damage-associated molecular pattern on adaptive responses remains largely unknown. In this study, we report that, in the presence of NF-κB signaling, uric acid crystals were capable of stimulating dendritic cells to promote the release of cytokines associated with Th17 polarization. Accordingly, naive CD4(+) T cells cocultured with uric acid-treated dendritic cells differentiated toward the Th17 lineage. Th17 differentiation required the inflammasome-dependent cytokines IL-1α/ß and IL-18 in both in vitro and in vivo models, and the inflammasome adaptor protein ASC and caspase-1 were essential for Th17 responses. Collectively, our findings indicate a novel role for the danger signal uric acid, in cooperation with NF-κB activation, in driving proinflammatory Th17 differentiation. Our data indicate that sterile inflammation shapes adaptive immunity, in addition to influencing early innate responses.

Discovery and characterization of 2-aminobenzimidazole derivatives as selective NOD1 inhibitors.

NLR family proteins play important roles in innate immune response. NOD1 (NLRC1) activates various signaling pathways including NF-κB in response to bacterial ligands. Hereditary polymorphisms in the NOD1 gene are associated with asthma, inflammatory bowel disease, and other disorders. Using a high throughput screening (HTS) assay measuring NOD1-induced NF-κB reporter gene activity, followed by multiple downstream counter screens that eliminated compounds impacting other NF-κB effectors, 2-aminobenzimidazole compounds were identified that selectively inhibit NOD1. Mechanistic studies of a prototypical compound, Nodinitib-1 (ML130; CID-1088438), suggest that these small molecules cause conformational changes of NOD1 in vitro and alter NOD1 subcellular targeting in cells. Altogether, this inaugural class of inhibitors provides chemical probes for interrogating mechanisms regulating NOD1 activity and tools for exploring the roles of NOD1 in various infectious and inflammatory diseases.

Effect of diffusion-sensitizing gradient timings on the exponential, biexponential and diffusional kurtosis model parameters: in-vivo measurements in the rat thalamus.

OBJECT: To investigate whether spacing (Delta) and duration (delta) of the diffusion-sensitizing gradient pulses differentially affect exponential (D'), biexponential (D (slow), D (fast) and f (slow)) and diffusional kurtosis (D and K) model parameters. METHODS: Measurements were performed in the rat thalamus for b = 200-3,200 s mm(-2), sweeping Delta between 20 and 100 ms at delta = 15 ms, and delta between 15 and 50 ms at Delta = 60 ms. Linear regressions were performed for each model parameter vs. Delta or delta. RESULTS: Increasing Delta from 20 to 100 ms increases D' (from 0.64 to 0.70 x 10(-3) mm(2)s(-1)) and D (slow) (from 0.26 to 0.33 x 10(-3) mm(2)s(-1)), reduces K (from 0.57 to 0.53), and has no effects on D (fast), f (slow) or D. Increasing delta from 15 to 50 ms increases D (from 0.80 to 0.88 x 10(-3) mm(2)s(-1)), and has no effects on the other parameters. CONCLUSION: The parameters of the biexponential and diffusional kurtosis models are more sensitive than the exponential model to Delta and delta; however, observed effects are too small to account for the discrepancies found in literature.

Different patterns of neuronal activation and neurodegeneration in the thalamus and cortex of epilepsy-resistant Proechimys rats versus Wistar rats after pilocarpine-induced protracted seizures.

PURPOSE: To analyze cellular mechanisms of limbic-seizure suppression, the response to pilocarpine-induced seizures was investigated in cortex and thalamus, comparing epilepsy-resistant rats Proechimys guyannensis with Wistar rats. METHODS: Fos immunoreactivity revealing neuronal activation, and degenerating neurons labeled by Fluoro-Jade B (FJB) histochemistry were analyzed on the first day after onset of seizures lasting 3 h. Subpopulations of gamma-aminobutyric acid (GABA)ergic cells were characterized with double Fos-parvalbumin immunohistochemistry. RESULTS: In both cortex and thalamus, degenerating neurons were much fewer in Proechimys than Wistar rats. Fos persisted at high levels at 24 h only in the Proechimys thalamus and cortex, especially in layer VI where corticothalamic neurons reside. In the parietal cortex, about 50% of parvalbumin-containing interneurons at 8 h, and 10-20% at 24 h, were Fos-positive in Wistar rats, but in Proechimys, Fos was expressed in almost all parvalbumin-containing interneurons at 8 h and dropped at 24 h. Fos positivity in cingulate cortex interneurons was similar in both species. In the Wistar rat thalamus, Fos was induced in medial and midline nuclei up to 8 h, when <30% of reticular nucleus cells were Fos-positive, and then decreased, with no relationship with cell loss, evaluated in Nissl-stained sections. In Proechimys, almost all reticular nucleus neurons were Fos-positive at 24 h. DISCUSSION: At variance with laboratory rats, pilocarpine-induced protracted seizures elicit in Proechimys limited neuronal death, and marked and long-lasting Fos induction in excitatory and inhibitory cortical and thalamic cell subsets. The findings implicate intrathalamic and intracortical regulation, and circuits linking thalamus and cortex in limbic seizure suppression leading to epilepsy resistance.

Modification of GABA(B1) and GABA(B2) receptor subunits in the somatosensory cerebral cortex and thalamus of rats with absence seizures (GAERS).

In the present study, we have investigated GABA(B) receptor expression in somatosensory cortex (S1) and the ventrobasal (VB) and reticular (Rt) thalamic nuclei of Genetic Absence Epilepsy Rats from Strasbourg (GAERS), which represent an animal model for the human absence epilepsy. We focused our attention on the thalamocortical network because it has been demonstrated that absence seizures are generated in this specific circuit, which is under the control of several inhibitory, e.g. GABA, and excitatory systems. Autoradiography data obtained with the GABA(B) receptor antagonist [3H]CGP62349 did not show any differences in Kd or Bmax values between control rats and GAERS. In situ hybridisation (ISH) results showed a significant increase in messenger RNA for GABA(B1) in the S1 and a decrease in the VB thalamic nucleus but not in the Rt thalamic nucleus. By contrast the immunocytochemical data revealed an increased expression of both GABA(B1) and GABA(B2) receptor subunits in all the regions examined, somatosensory cerebral cortex, VB thalamus and Rt nucleus in GAERS compared to controls. The main finding was an up-regulation of GABA(B) receptor protein in the corticothalamic circuit in GAERS compared to controls.