Reviews & Analysis

The regulation of T cell survival and apoptosis contributes to the pathogenesis of autoimmune disease. A new study shows that the transcriptional regulator β-arrestin 1 enhances antiapoptotic Bcl-2 in T cells, which can heighten autoimmune disease.

Tapasin enhances the loading and editing of peptide 'cargo' onto major histocompatibility complex class I molecules, yet it cannot do so alone. Two new reports show that the oxidoreductase ERp57 assists tapasin in these activities.

Time- and tissue-specific recombination of antigen-receptor genes is regulated in part by locus accessibility. New evidence demonstrates a specific function for nucleosome remodeling in the T cell receptor-β locus to allow recombination in thymocytes.

Toll-like receptors respond to ligands embedded in pathogen-derived macromolecules to induce immune responses. Binding of a stimulatory ligand to preexisting dimers of Toll-like receptor 9 induces conformational changes that lead to their full activation.

Allelic exclusion acts to ensure lymphocytes express only one antigen receptor on their surfaces. Differences in DNA methylation are now shown to distinguish alleles for subsequent somatic hypermutation steps leading to antibody affinity maturation.

Intensive characterization of the locus encoding interferon-γ provides new insight into how proper gene expression is achieved in polarizing T cells. NOTE: In the version of this News & Views initially published, the figure credit is missing. This figure should be credited to Ann Thomson. The error has been corrected in the HTML and PDF versions of the article.

New evidence demonstrates how two different effector T cell subsets traffic in reactive lymph nodes to modulate T cell and B cell responses.

Multiple receptors alert cells to microbial invasion by initiating intracellular signals that modify gene expression. New work provides a more complex view of microbe-induced signaling through the adaptor CARD9.

Human immunodeficiency virus uses many signaling pathways and cell surface receptors to infect cells. New work emphasizes the many functions of the lectin DC-SIGN expressed in dendritic cells.

Dendritic cells are specialized in antigen presentation to lymphocytes. New research clarifies the origin and kinetics of differentiation of a subset of dendritic cells in the spleen and lymph nodes.

AID acts to further refine the immunoglobulin response in fish, birds and mammals. Now, evidence is uncovered to suggest AID actually arose early in evolution and can diversify antigen receptors in lampreys.

Fungal recognition occurs partially through the C-type lectin dectin-1. New studies show that dectin-mediated immune recognition of Candida albicans induces the differentiation of interleukin 17–producing T helper cells that express chemokine receptors characteristic of mucosal homing.

The immune system has several signaling pathways that detect invading pathogens. When activated in certain conditions, these pathways can also serve to exacerbate or even cause autoimmune disease.

Smad7 controls inflammation by negatively regulating activation of the transcription factor NF-κB. New work shows that Smad7 inhibits NF-κB by binding to the regulatory proteins TAB2 and TAB3, thereby blocking association of the E3 ubiquitin ligase TRAF2 with the kinase TAK1.

Self-reactive B cells are subject to several mechanisms to ensure self-tolerance. The epithelium-derived cytokine TSLP acts to regulate B cell tolerance by targeting B cell precursors rather than mature B cells.

Epithelial NF-κB preserves the integrity of the gut epithelial barrier and coordinates the antimicrobial actions of the innate and adaptive immune systems. Deficiency in or hyperactivation of this transcription factor results in chronic inflammatory bowel disease.

The transcriptional regulators Foxp3 and Aire have key functions in self-tolerance. New studies emphasize potential links between Aire-expressing thymic stromal cells and the development of Foxp3-expressing regulatory T cells.