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The cytokine interleukin-17A/F (IL-17A/F) not only protects the skin and mucosae against Candida albicans infection in mice and humans but also promotes autoimmunity and autoinflammation in mice. In this issue of Science Signaling, Amatya et al. report that the RNA binding protein Arid5a promotes responses to IL-17A/F through multiple mechanisms.

PurposeInborn errors of IFN--mediated immunity underlie Mendelian Susceptibility to Mycobacterial Disease (MSMD), which is characterized by an increased susceptibility to severe and recurrent infections caused by weakly virulent mycobacteria, such as Bacillus Calmette-Guerin (BCG) vaccines and environmental, nontuberculous mycobacteria (NTM).MethodsIn this study, we investigated four patients from four unrelated consanguineous families from Isfahan, Iran, with disseminated BCG disease. We evaluated the patients' whole blood cell response to IL-12 and IFN-, IL-12R1 expression on T cell blasts, and sequenced candidate genes.ResultsWe report four patients from Isfahan, Iran, ranging from 3months to 26years old, with impaired IL-12 signaling. All patients suffered from BCG disease. One of them presented mycobacterial osteomyelitis. By Sanger sequencing, we identified three different types of homozygous mutations in IL12RB1. Expression of IL-12R1 was completely abolished in the four patients with IL12RB1 mutations.ConclusionsIL-12R1 deficiency was found in the four MSMD Iranian families tested. It is the first report of an Iranian case with S321* mutant IL-12R1 protein. Mycobacterial osteomyelitis is another type of location of BCG infection in an IL-12R1-deficient patient, notified for the first time in this study.

Immune stimulation has emerged as a promising approach to the treatment of neoplastic diseases. Currently approved therapeutics, such as anti-CTLA4 and anti-PD1, are primarily aimed at blocking inhibitory signaling by immune cells. An alternative and potentially synergistic approach would involve activation of immune pathways by agonism of stimulatory receptors, such as CD40. Agonistic antibodies, while promising in principle, have encountered significant barriers in clinical trials limited by the systemic toxicity of such approaches. Using a mouse model humanized for both Fc receptors and CD40, we previously demonstrated enhanced antitumor activity with an Fc-modified antibody. We now demonstrate that this model recapitulates the platelet and hepatic toxicities seen with anti-CD40 antibodies in patients, providing a predictive measure of the dose-limiting activity of this approach. We further show that such toxicity can be circumvented and durable systemic antitumor immunity achieved by intratumoral delivery of an Fc-engineered anti-CD40 agonistic antibody.

Rifamycin antibiotics (Rifs) target bacterial RNA polymerases (RNAPs) and are widely used to treat infections including tuberculosis. The utility of these compounds is threatened by the increasing incidence of resistance (Rif(R)). As resistance mechanisms found in clinical settings may also occur in natural environments, here we postulated that bacteria could have evolved to produce rifamycin congeners active against clinically relevant resistance phenotypes. We survey soil metagenomes and identify a tailoring enzyme-rich family of gene clusters encoding biosynthesis of rifamycin congeners (kanglemycins, Kangs) with potent in vivo and in vitro activity against the most common clinically relevant Rif(R) mutations. Our structural and mechanistic analyses reveal the basis for Kang inhibition of Rif(R) RNAP. Unlike Rifs, Kangs function through a mechanism that includes interfering with 5'-initiating substrate binding. Our results suggest that examining soil microbiomes for new analogues of clinically used antibiotics may uncover metabolites capable of circumventing clinically important resistance mechanisms.

Cell biological studies have shown that protofilament number, a fundamental feature of microtubules, can correlate with the expression of different tubulin isotypes. However, it is not known if tubulin isotypes directly control this basic microtubule property. Here, we report high-resolution cryo-EM reconstructions (3.5-3.65 angstrom) of purified human alpha 1B/beta 3 and alpha 1B/beta 2B microtubules and find that the beta-tubulin isotype can determine protofilament number. Comparisons of atomic models of 13- and 14-protofilament microtubules reveal how tubulin subunit plasticity, manifested in "accordion-like" distributed structural changes, can accommodate distinct lattice organizations. Furthermore, compared to alpha 1B/beta 3 microtubules, alpha 1B/beta 2B filaments are more stable to passive disassembly and against depolymerization by MCAK or chTOG, microtubule-associated proteins with distinct mechanisms of action. Mixing tubulin isotypes in different proportions results in microtubules with protofilament numbers and stabilities intermediate to those of isotypically pure filaments. Together, our findings indicate that microtubule protofilament number and stability can be controlled through beta-tubulin isotype composition.

We developed a method for rapid generation of B cell receptor (BCR) monoclonal mice expressing prerearranged Igh and Igk chains monoallelically from the Igh locus by CRI SPR-Cas9 injection into fertilized oocytes. B cells from these mice undergo somatic hypermutation (SHM), class switch recombination (CSR), and affinity-based selection in germinal centers. This method combines the practicality of BCR transgenes with the ability to study Ig SHM, CSR, and affinity maturation.

Objectives: We present the results of two European external quality assessments (EQAs) conducted in 2014 and 2016 under the auspices of the Study Group on Staphylococci and Staphylococcal Infections of ESCMID. The objective was to assess the performance of participating centres in characterizing Staphylococcus aureus using their standard in-house phenotypic and genotypic protocols. Methods: A total of 11 well-characterized blindly coded S. aureus (n = 9), Staphylococcus argenteus (n = 1) and Staphylococcus capitis (n = 1) strains were distributed to participants for analysis. Species identification, MIC determination, antimicrobial susceptibility testing, antimicrobial resistance and toxin gene detection and molecular typing including spa typing, SCCmec typing and MLST were performed. Results: Thirteen laboratories from 12 European countries participated in one EQA or both EQAs. Despite considerable diversity in the methods employed, good concordance (90%-100%) with expected results was obtained. Discrepancies were observed for: (i) identification of the S. argenteus strain; (ii) phenotypic detection of low-level resistance to oxacillin in the mecC-positive strain; (iii) phenotypic detection of the inducible MLSB strain; and (iv) WGS-based detection of some resistance and toxin genes. Conclusions: Overall, good concordance (90%-100%) with expected results was observed. In some instances, the accurate detection of resistance and toxin genes from WGS data proved problematic, highlighting the need for validated and internationally agreed-on bioinformatics pipelines before such techniques are implemented routinely by microbiology laboratories. We strongly recommend all national reference laboratories and laboratories acting as referral centres to participate in such EQA initiatives.

The commonly mutated genes in pancreatic neuroendocrine tumors (PanNETs) are ATRX, DAXX, and MEN1. We genotyped 64 PanNETs and found 58% carry ATRX, DAXX, and MEN1 mutations (A-D-M mutant PanNETs) and this correlates with a worse clinical outcome than tumors carrying the wild-type alleles of all three genes (A-D-M WT PanNETs). We performed RNA sequencing and DNA-methylation analysis to reveal two distinct subgroups with one consisting entirely of A-D-M mutant PanNETs. Two genes differentiating A-D-M mutant from A-D-M WT PanNETs were high ARX and low PDX1 gene expression with PDX1 promoter hyper-methylation in the A-D-M mutant PanNETs. Moreover, A-D-M mutant PanNETs had a gene expression signature related to that of alpha-cells (FDR q-value < 0.009) of pancreatic islets including increased expression of HNF1A and its transcriptional target genes. This gene expression profile suggests that A-D-M mutant PanNETs originate from or transdifferentiate into a distinct cell type similar to alpha cells.