Summary Anergic B cells are characterized by impaired signaling and activation following aggregation of their antigen receptors (BCR). The molecular basis of this impairment is not understood. In studies reported here Src homology-2 (SH2)-containing inositol 5-phosphatase SHIP-1 and its adaptor Dok-1 were found to be constitutively phosphorylated in anergic B cells, and activation of this inhibitory circuit was dependent on Src-family kinase activity and consequent to biased BCR immunoreceptor tyrosine-based activation motif (ITAM) monophosphorylation. B cell-targeted deletion of SHIP-1 caused severe lupus-like disease. Moreover, absence of SHIP-1 in B cells led to loss of anergy as indicated by restoration of BCR signaling, loss of anergic surface phenotype and production of autoantibodies. Thus chronic BCR signals maintain anergy in part via ITAM monophosphorylation-directed activation of an inhibitory signaling circuit involving SHIP-1 and Dok-1.

SummaryBackgroundIntradermal MVA85A, a candidate vaccine against tuberculosis, induces high amounts of Ag85A-specific CD4 T cells in adults who have already received the BCG vaccine, but aerosol delivery of this vaccine might offer immunological and logistical advantages. We did a phase 1 double-blind trial to compare the safety and immunogenicity of aerosol-administered and intradermally administered MVA85AMethodsIn this phase 1, double-blind, proof-of-concept trial, 24 eligible BCG-vaccinated healthy UK adults were randomly allocated (1:1) by sequentially numbered, sealed, opaque envelopes into two groups: aerosol MVA85A and intradermal saline placebo or intradermal MVA85A and aerosol saline placebo. Participants, the bronchoscopist, and immunologists were masked to treatment assignment. The primary outcome was safety, assessed by the frequency and severity of vaccine-related local and systemic adverse events. The secondary outcome was immunogenicity assessed with laboratory markers of cell-mediated immunity in blood and bronchoalveolar lavage samples. Safety and immunogenicity were assessed for 24 weeks after vaccination. Immunogenicity to both insert Ag85A and vector modified vaccinia virus Ankara (MVA) was assessed by ex-vivo interferon-γ ELISpot and serum ELISAs. Since all participants were randomised and vaccinated according to protocol, our analyses were per protocol. This trial is registered with ClinicalTrials.gov, number NCT01497769.FindingsBoth administration routes were well tolerated and immunogenic. Respiratory adverse events were rare and mild. Intradermal MVA85A was associated with expected mild local injection-site reactions. Systemic adverse events did not differ significantly between the two groups. Three participants in each group had no vaccine-related systemic adverse events; fatigue (11/24 [46%]) and headache (10/24 [42%]) were the most frequently reported symptoms. Ag85A-specific systemic responses were similar across groups. Ag85A-specific CD4 T cells were detected in bronchoalveolar lavage cells from both groups and responses were higher in the aerosol group than in the intradermal group. MVA-specific cellular responses were detected in both groups, whereas serum antibodies to MVA were only detectable after intradermal administration of the vaccine.InterpretationFurther clinical trials assessing the aerosol route of vaccine delivery are merited for tuberculosis and other respiratory pathogens.FundingThe Wellcome Trust and Oxford Radcliffe Hospitals Biomedical Research Centre.

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Although dogma predicts that under normal circumstances, potentially offensive autoreactive cells are silenced by mechanisms of immune tolerance, islet antigen–reactive B lymphocytes are known to play a crucial role in the development of autoimmunity in type 1 diabetes (T1D). Thus, participation of these cells in T1D may reflect escape from silencing mechanisms. Consistent with this concept, we found that in healthy subjects, high-affinity insulin-binding B cells occur exclusively in the anergic naive IgD+, IgM− B-cell (BND) compartment. Antigen receptors expressed by these cells are polyreactive and have N-region additions, Vh usage, and charged complementarity-determining region 3 consistent with autoreactivity. Consistent with a potential early role in autoimmunity, these high-affinity insulin-binding B cells are absent from the anergic compartment of some first-degree relatives and all prediabetic and new-onset (<1 year) T1D patients tested, but return to normal levels in individuals diabetic for >1 year. Interestingly, these changes were correlated by transient loss of the entire BND compartment. These findings suggest that environmental events such as infection or injury may, by disrupting B-cell anergy, dispose individuals toward autoimmunity, the precise nature of which is specified by genetic risk factors, such as HLA alleles.