Allelic-Dependent Expression of an Activating Fc Receptor on B Cells Enhances Humoral Immune Responses In both human B cells and B cells from mice transgenic for human FcγRIIc, FcγRIIc expression counterbalances the negative feedback of FcγRIIb and enhances humoral responses to immunization in mice and to BioThrax vaccination in a human anthrax vaccine trial. [Sci Transl Med] Abstract | Press Release Transcription Factor IRF4 Drives Dendritic Cells to Promote Th2 Differentiation Researchers demonstrated that Th2-promoting stimuli induces dendritic cell (DC) expression of IRF4. Mice with conditional deletion of Irf4 in DCs showed a dramatic defect in Th2-type lung inflammation, yet retain the ability to elicit pulmonary Th1 antiviral responses. [Nat Commun] Abstract Halofuginone Ameliorates Autoimmune Arthritis by Regulating the Balance between Th17 and Regulatory T Cells and Inhibiting Osteoclastogenesis Treatment with halofuginone (HF) suppressed the development of autoimmune arthritis and reciprocally regulated Th17 cell and Foxp3+ regulatory T cells. The effects of HF on Th17 differentiation involved increased signaling of extracellular signal-regulated kinase, and reduction of signal transducer and activator of transcription 3 and nuclear factor of activated T cells cytoplasmic 1 expression. [Arthritis Rheum] Abstract STA-21, a Promising STAT3 Inhibitor that Reciprocally Regulates Th17 and Treg, Inhibits Osteoclastogenesis and Alleviates Autoimmune Inflammation The authors investigated the impact of STA-21, a promising STAT3 inhibitor, on inflammatory arthritis and the possible mechanisms by which STA-21 has anti-arthritic effects in animal model of rheumatoid arthritis (IL-1 receptor antagonist deficient mice). [Arthritis Rheum] Abstract Altered Inactivation of Commensal LPS Due to Acyloxyacyl Hydrolase Deficiency in Colonic Dendritic Cells Impairs Mucosal Th17 Immunity Investigators found that LPS-containing Gram-negative microbiota augmented the differentiation of antigen-specific interleukin 17-secreting CD4+ helper T (Th17) cells, and identified a colonic dendritic cell subset (CD103+CD11b+ALDH–) displaying a unique capacity to both express acyloxyacyl hydrolase and polarize Th17 cells. [Proc Natl Acad Sci USA] Abstract Cell-Extrinsic CTLA4-Mediated Regulation of Dendritic Cell Maturation Depends on STAT3 Scientists demonstrated that stimulation of dendritic cells (DCs) with cytotoxic T lymphocyte antigen 4 (CTLA4), either expressed by inducible regulatory T cells or by cross-linking with CTLA4Fc fusion protein, can significantly inhibit LPS-induced CD80 and CD86 mRNA and protein expression in both mouse and human DCs. [Eur J Immunol] Abstract In Vivo and In Vitro Characterization of the Immune Stimulating Activity of the Neisserial Porin PorB Scientists demonstrated NFκB translocation following stimulation with Porin B (PorB) only occurs in the presence of toll-like receptor 2 (TLR2). IL-6 and TNF-α secretion was shown to be MAPK dependent. Surface expression of activation markers on macrophages, including CD40, CD69, and CD86, was increased following PorB stimulation in vitro. [PLoS One] Full Article |