Novel Foxo1-Dependent Transcriptional Programs Control Treg Cell Function Findings showed that the evolutionarily ancient Akt-forkhead box O-1 (Foxo1) signaling module controls a novel genetic program indispensable for regulatory T (Treg) cell function. [Nature] Abstract SAMHD1 Restricts HIV-1 Infection in Resting CD4+ T Cells Researchers showed that the deoxynucleoside triphosphate triphosphohydrolase SAMHD1 prevents reverse transcription of HIV-1 RNA in resting CD4+ T cells. [Nat Med] Abstract Neutrophils Transport Antigen from the Dermis to the Bone Marrow, Initiating a Source of Memory CD8+ T Cells Researchers found that after intradermal injection of modified vaccinia Ankara virus, unexpected sources of newly primed polyclonal virus-specific CD8+, but not CD4+, T cells were localized in the bone marrow (BM) and the draining lymph nodes prior to blood circulation. They provide direct evidence for how antigen is transported to the BM, providing a source of virus-specific memory CD8+ T cells. [Immunity] Abstract TLR4 and TRIF-Dependent Stimulation of B Lymphocytes by Peptide Liposomes Enables T-Cell Independent Isotype Switch in Mice Investigators demonstrated that peptides can induce T-cell independent isotype switching when antigen and TLR ligand are assembled and appropriately presented directly to B lymphocytes. [Blood] Abstract Macrophage Microvesicles Induce Macrophage Differentiation and miR-223 Transfer Researchers characterized macrophage-derived microvesicles and explored their role in the differentiation of naïve monocytes. They also identified the microRNA (miRNA) content of the macrophage-derived microvesicles. [Blood] Abstract Encounter with Antigen-Specific Primed CD4 T Cells Promotes MHC Class II Degradation in Dendritic Cells Scientists investigated whether antigen-loaded dendritic cells (DCs) that have been in contact with antigen-specific CD4 T cells retain the ability to stimulate additional naïve T cells. They showed that the encounter with antigen-specific primed CD4 T cells induces the degradation of surface major histocompatibility complex class II molecules (MHC-II) in antigen-loaded DCs and inhibits the ability of these DCs to stimulate additional naïve CD4 T cells. [Proc Natl Acad Sci USA] Abstract IL-7 Abrogates Suppressive Activity of Human CD4+CD25+FOXP3+ Regulatory T Cells and Allows Expansion of Alloreactive and Autoreactive T Cells Because uncontrolled activation and expansion of autoreactive T cells occur in an IL-7-rich environment, researchers explored the possibility that IL-7 may affect the function of CD4+CD25+FOXP3+ regulatory T cells. [J Immunol] Abstract Ex Vivo Enzymatic Treatment of Aged CD4 T Cells Restores Cognate T Cell Helper Function and Enhances Antibody Production in Mice By using an in vivo model of the immune response based on adoptive transfer of CD4 T cells from pigeon cytochrome C-specific transgenic H-2(k/k) TCR-Vα11Vβ3 CD4+ mice to syngeneic hosts, the authors demonstrated that aging diminishes CD28 costimulatory signals in CD4 T cells. They also showed that the age-related decline in CD4 cognate helper function for IgG production and long-term humoral immunity can also be restored by O-sialoglycoprotein endopeptidase treatment of CD4 T cells prior to adoptive transfer. [J Immunol] Abstract Type II Collagen Induces Peripheral Tolerance in BALB/c Mice via the Generation of CD8+ T Regulatory Cells Researchers performed functional local adoptive transfer assays to examine the regulatory roles of spleen cells, T cells, and CD8+ T cells in the specific immune regulation induced by type-II collagen injection into the anterior chamber of the eye. [PLoS One] Full Article Plasmacytoid Dendritic Cells Have a Cytokine-Producing Capacity to Enhance ICOS Ligand-Mediated IL-10 Production during T-Cell Priming Researchers found that either IFN-α or IL-6 enhanced the plasmacytoid dendritic cell- or inducible co-stimulatory ligand (ICOS-L)-driven generation of IL-10-producing T-cells from naive CD4+ T-cells and their regulatory functions. [Int Immunol] Abstract |