HIV-1 Adaptation to NK-Cell-Mediated Immune Pressure The data demonstrates that killer immunoglobulin-like receptor (KIR)-positive natural killer (NK) cells can place immunological pressure on HIV-1, and that the virus can evade such NK-cell-mediated immune pressure by selecting for sequence polymorphisms. [Nature] A Critical Role for TCF-1 in T-Lineage Specification and Differentiation Here researchers show that a transcription factor, T-cell factor 1 (TCF-1; also known as transcription factor 7, T-cell specific, TCF7), is a critical regulator in T-cell specification. [Nature] A Neutralizing Antibody Selected from Plasma Cells That Binds to Group 1 and Group 2 Influenza A Hemagglutinins Using a single-cell culture method for screening large numbers of human plasma cells, researchers isolated a neutralizing monoclonal antibody that recognized the hemagglutinin glycoprotein of all 16 subtypes and neutralized both group 1 and group 2 influenza A viruses. [Science] Indoleamine 2,3-Dioxygenase Is a Signaling Protein in Long-Term Tolerance by Dendritic Cells Here investigators show that treatment of mouse plasmacytoid dendritic cells with transforming growth factor-β conferred regulatory effects on indoleamine 2,3-dioxygenase that were mechanistically separable from its enzymic activity. [Nat Immunol] Autocrine IL-2 Is Required for Secondary Population Expansion of CD8+ Memory T Cells Researchers investigated the requirement for IL-2 by the relevant three cell types in vivo and found that CD8+ T cells, rather than CD4+ T cells or dendritic cells, produced the IL-2 necessary for CD8+ T cell memory. [Nat Immunol] Recognition of β-Linked Self Glycolipids Mediated by Natural Killer T Cell Antigen Receptors Here researchers provide the mechanism for the autoreactivity of T cell antigen receptors on natural killer T cells to the mono- and tri-glycosylated β-linked agonists β-galactosylceramide and isoglobotrihexosylceramide, respectively. [Nat Immunol] NIK Signaling in Dendritic Cells but Not in T Cells Is Required for the Development of Effector T Cells and Cell-Mediated Immune Responses Upon systematic analysis of NF-κB–inducing kinase (NIK) function in cell-mediated immunity, researchers found that NIK signaling is dispensable within CD4+ T cells but played a pivotal role in dendritic cells. [J Exp Med] Nonrandom Attrition of the Naive CD8+ T-Cell Pool with Aging Governed by T-Cell Receptor:pMHC Interactions T-cell receptor avidity for self-pMHC provides a proofreading mechanism to maintain some of the fittest T cells in the otherwise crumbling naive repertoire, providing a degree of compensation for numerical and diversity defects in old T cells. [Proc Nat Acad Sci USA] Thy1+ NK Cells from Vaccinia Virus-Primed Mice Confer Protection Against Vaccinia Virus Challenge in the Absence of Adaptive Lymphocytes The results demonstrate that a defined innate memory cell population alone can provide host protection against a lethal systemic infection through viral clearance. [PLoS Pathog] Human B Cells Differentiate into Granzyme B-Secreting Cytotoxic B Lymphocytes Upon Incomplete T-Cell Help In the present study researchers show, that in the absence of CD40L, CD4+ T cell-derived IL-21 induces differentiation of B cells into granzyme B (GzmB)-secreting cytotoxic cells. [Immunol Cell Biol] |