The non-benzodiazepine anxiolytic etifoxine limits mechanical allodynia and anxiety-like symptoms in a mouse model of streptozotocin-induced diabetic neuropathy.

More than 450 million people worldwide suffer from diabetes, or 1 in 11 people. Chronic hyperglycemia degrades patients' quality of life and the development of neuropathic pain contributes to the burden of this disease. In this study, we used the mouse model of streptozocin-induced diabetic type 1 neuropathy to assess the analgesic potential of etifoxine. Etifoxine is a prescribed anxiolytic that increases GABAAA receptor function through a direct positive allosteric modulation effect and, indirectly, by stimulating the production of endogenous GABAA receptor positive modulators such as allopregnanolone-type neurosteroids. We show that a post-symptomatic or preventive treatment strongly and durably reduces mechanical hyperalgesia and anxiety in diabetic neuropathic mice. This analgesic and neuroprotective effect on painful symptoms and emotional comorbidities is promising and should now be clinically evaluated.

Immune history profoundly affects broadly protective B cell responses to influenza.

Generating a broadly protective influenza vaccine is critical to global health. Understanding how immune memory influences influenza immunity is central to this goal. We undertook an in-depth study of the B cell response to the pandemic 2009 H1N1 vaccine over consecutive years. Analysis of monoclonal antibodies generated from vaccine-induced plasmablasts demonstrated that individuals with low preexisting serological titers to the vaccinating strain generated a broadly reactive, hemagglutinin (HA) stalk-biased response. Higher preexisting serum antibody levels correlated with a strain-specific HA head-dominated response. We demonstrate that this HA head immunodominance encompasses poor accessibility of the HA stalk epitopes. Further, we show polyreactivity of HA stalk-reactive antibodies that could cause counterselection of these cells. Thus, preexisting memory B cells against HA head epitopes predominate, inhibiting a broadly protective response against the HA stalk upon revaccination with similar strains. Consideration of influenza exposure history is critical for new vaccine strategies designed to elicit broadly neutralizing antibodies.

Preexisting human antibodies neutralize recently emerged H7N9 influenza strains.

The emergence and seasonal persistence of pathogenic H7N9 influenza viruses in China have raised concerns about the pandemic potential of this strain, which, if realized, would have a substantial effect on global health and economies. H7N9 viruses are able to bind to human sialic acid receptors and are also able to develop resistance to neuraminidase inhibitors without a loss in fitness. It is not clear whether prior exposure to circulating human influenza viruses or influenza vaccination confers immunity to H7N9 strains. Here, we demonstrate that 3 of 83 H3 HA-reactive monoclonal antibodies generated by individuals that had previously undergone influenza A virus vaccination were able to neutralize H7N9 viruses and protect mice against homologous challenge. The H7N9-neutralizing antibodies bound to the HA stalk domain but exhibited a difference in their breadth of reactivity to different H7 influenza subtypes. Mapping viral escape mutations suggested that these antibodies bind at least two different epitopes on the stalk region. Together, these results indicate that these broadly neutralizing antibodies may contribute to the development of therapies against H7N9 strains and may also be effective against pathogenic H7 strains that emerge in the future.

Vimentin is a dominant target of in situ humoral immunity in human lupus tubulointerstitial nephritis.

OBJECTIVE: In lupus nephritis (LN), severe tubulointerstitial inflammation (TII) predicts progression to renal failure. Severe TII is associated with tertiary lymphoid neogenesis and in situ antigen-driven clonal B cell selection. The autoantigen(s) driving in situ B cell selection in TII are not known. This study was undertaken to identify the dominant driving autoantigen(s). METHODS: Single CD38+ or Ki-67+ B cells were laser captured from 7 biopsy specimens that were diagnostic for LN. Eighteen clonally expanded immunoglobulin heavy- and light-chain variable region pairs were cloned and expressed as monoclonal antibodies. Seven more antibodies were cloned from flow-sorted CD38+ cells from an eighth biopsy specimen. Antigen characterization was performed using a combination of confocal microscopy, enzyme-linked immunosorbent assay, screening protoarrays, immunoprecipitation, and mass spectrometry. Serum IgG titers to the dominant antigen in 48 LN and 35 non-nephritic lupus samples were determined using purified antigen-coated arrays. Autoantigen expression on normal and LN kidney was localized by immunohistochemistry and immunofluorescence. RESULTS: Eleven of 25 antibodies reacted with cytoplasmic structures, 4 reacted with nuclei, and none reacted with double-stranded DNA. Vimentin was the only autoantigen identified by both mass spectrometry and protoarray. Ten of the 11 anticytoplasmic TII antibodies directly bound vimentin. Vimentin was highly expressed by tubulointerstitial inflammatory cells, and the TII antibodies tested preferentially bound inflamed tubulointerstitium. Finally, high titers of serum antivimentin antibodies were associated with severe TII (P = 0.0001). CONCLUSION: Vimentin, an antigenic feature of inflammation, is a dominant autoantigen targeted in situ in LN TII. This adaptive autoimmune response likely feeds forward to worsen TII and renal damage.

Restricted VH/VL usage and limited mutations in gluten-specific IgA of coeliac disease lesion plasma cells.

Coeliac disease (CD), an enteropathy caused by cereal gluten ingestion, is characterized by CD4(+) T cells recognizing deamidated gluten and by antibodies reactive to gluten or the self-antigen transglutaminase 2 (TG2). TG2-specific immunoglobulin A (IgA) of plasma cells (PCs) from CD lesions have limited somatic hypermutation (SHM). Here we report that gluten-specific IgA of lesion-resident PCs share this feature. Monoclonal antibodies were expression cloned from single PCs of patients either isolated from cultures with reactivity to complex deamidated gluten antigen or by sorting with gluten peptide tetramers. Typically, the antibodies bind gluten peptides related to T-cell epitopes and many have higher reactivity to deamidated peptides. There is restricted VH and VL combination and usage among the antibodies. Limited SHM suggests that a common factor governs the mutation level in PCs producing TG2- and gluten-specific IgA. The antibodies have potential use for diagnosis of CD and for detection of gluten.