Genetic dissection of TLR9 reveals complex regulatory and cryptic proinflammatory roles in mouse lupus.

In lupus, Toll-like receptor 7 (TLR7) and TLR9 mediate loss of tolerance to RNA and DNA, respectively. Yet, TLR7 promotes disease, while TLR9 protects from disease, implying differences in signaling. To dissect this 'TLR paradox', we generated two TLR9 point mutants (lacking either ligand (TLR9K51E) or MyD88 (TLR9P915H) binding) in lupus-prone MRL/lpr mice. Ameliorated disease of Tlr9K51E mice compared to Tlr9-/- controls revealed a TLR9 'scaffold' protective function that is ligand and MyD88 independent. Unexpectedly, Tlr9P915H mice were more protected than both Tlr9K51E and Tlr9WT mice, suggesting that TLR9 also possesses ligand-dependent, but MyD88-independent, regulatory signaling and MyD88-mediated proinflammatory signaling. Triple-mixed bone marrow chimeras showed that TLR9-MyD88-independent regulatory roles were B cell intrinsic and restrained differentiation into pathogenic age-associated B cells and plasmablasts. These studies reveal MyD88-independent regulatory roles of TLR9, shedding light on the biology of endosomal TLRs.

IL-10 Impairs Local Immune Response in Lung Granulomas and Lymph Nodes during Early Mycobacterium tuberculosis Infection.

Tuberculosis (TB), caused by Mycobacterium tuberculosis, continues to be a major global health problem. Lung granulomas are organized structures of host immune cells that function to contain the bacteria. Cytokine expression is a critical component of the protective immune response, but inappropriate cytokine expression can exacerbate TB. Although the importance of proinflammatory cytokines in controlling M. tuberculosis infection has been established, the effects of anti-inflammatory cytokines, such as IL-10, in TB are less well understood. To investigate the role of IL-10, we used an Ab to neutralize IL-10 in cynomolgus macaques during M. tuberculosis infection. Anti-IL-10-treated nonhuman primates had similar overall disease outcomes compared with untreated control nonhuman primates, but there were immunological changes in granulomas and lymph nodes from anti-IL-10-treated animals. There was less thoracic inflammation and increased cytokine production in lung granulomas and lymph nodes from IL-10-neutralized animals at 3-4 wk postinfection compared with control animals. At 8 wk postinfection, lung granulomas from IL-10-neutralized animals had reduced cytokine production but increased fibrosis relative to control animals. Although these immunological changes did not affect the overall disease burden during the first 8 wk of infection, we paired computational modeling to explore late infection dynamics. Our findings support that early changes occurring in the absence of IL-10 may lead to better bacterial control later during infection. These unique datasets provide insight into the contribution of IL-10 to the immunological balance necessary for granulomas to control bacterial burden and disease pathology in M. tuberculosis infection.

Age-associated B cells are heterogeneous and dynamic drivers of autoimmunity in mice.

Age-associated B cells (ABCs) are formed under inflammatory conditions and are considered a type of memory B cell (MBC) expressing the transcription factor T-bet. In SLE, ABC frequency is correlated with disease, and they are thought to be the source of autoantibody-secreting cells. However, in inflammatory conditions, whether autoreactive B cells can become resting MBCs is uncertain. Further, the phenotypic identity of ABCs and their relationship to other B cell subsets, such as plasmablasts, is unclear. Whether ABCs directly promote disease is untested. Here we report, in the MRL/lpr SLE model, unexpected heterogeneity among ABC-like cells for expression of the integrins CD11b and CD11c, T-bet, and memory or plasmablast markers. Transfer and labeling studies demonstrated that ABCs are dynamic, rapidly turning over. scRNA-seq identified B cell clones present in multiple subsets, revealing that ABCs can be plasmablast precursors or undergo cycles of reactivation. Deletion of CD11c-expressing B cells revealed a direct role for ABC-like B cells in lupus pathogenesis.

Draft Genome of Acidovorax kalamii Strain JM16, Isolated from Skin Mucus of Zebrafish (Danio rerio).

Acidovorax kalamii strain JM16 was isolated from the skin mucus of the zebrafish, Danio rerio. Its genome is 5.3 Mb with a 65.6% GC content and encodes quorum sensing capabilities, which could contribute to ecosystem functioning within the fish host skin bacterial community.

Draft Genome Sequence of Delftia tsuruhatensis Strain 45.2.2, Colonizer of Zebrafish, Danio rerio, Skin Mucus.

Delftia tsuruhatensis strain 45.2.2 is a member of the zebrafish, Danio rerio, skin mucus microbiota. Its genome is similar in size and GC content to those of other Delftia strains.

Spatial and Seasonal Patterns of the Mosquito Community in Central Oklahoma.

Mosquitoes (Culicidae) are ubiquitous flying insects that function as vectors for several viruses that cause disease in humans. Mosquito abundance and diversity are influenced by landscape features and environmental factors such as temperature and precipitation and vary across seasons and years. The range and phenology of many mosquito species that vector viruses relevant to human health are changing. We sampled mosquito communities in central Oklahoma for four years at thirteen sites, collecting over 25,000 mosquitoes; among these, we identified 27 different species, including several that transmit human pathogens and were collected in suburban backyards. Community composition differed across the landscape and changed from early season to late season and year to year. This effort to describe mosquito communities in Oklahoma is a first step toward assessing and predicting arbovirus risk, an ongoing and dynamic public health challenge.

Genome Sequences of Cluster G Mycobacteriophages Cambiare, FlagStaff, and MOOREtheMARYer.

Mycobacteriophages Cambiare, FlagStaff, and MOOREtheMARYer are newly isolated phages of Mycobacterium smegmatis mc(2) 155 recovered from soil samples in Pittsburgh, PA. All three genomes are closely related to cluster G mycobacteriophages but differ sufficiently in nucleotide sequence and gene content to warrant division of cluster G into several subclusters.