Volume 11 Issue 9, September 2010

The mechanisms driving IL-10 production by human T helper type 1 effector cells are poorly defined. New data link the complement regulator protein CD46 to this process and suggest an important role in autoimmune arthritis.

Mucosal IgA regulates the composition of gut microbiota. IgT in bony fish is now shown to have—via convergent evolution—the same properties as IgA, demonstrating strong evolutionary pressure to preserve both systemic and mucosal immunity.

Immunohomeostasis prevents pathology resulting from immune activation. Two new studies link its regulation with the activation of the aryl hydrocarbon receptor, a known mediator of the toxic effects of xenobiotic ligands, in a subset of T lymphocytes.

Although nickel allergy is very common, the specific receptor for nickel has not been identified. TLR4 is now shown to bind nickel and cause inflammation, an interaction that is specific to humans.

MicroRNAs regulate many biological processes, including the development of cells of the immune response. Liu et al. demonstrate that a decrease in particular microRNAs prevents macrophage hyperactivation but primes their responsiveness to proinflammatory stimuli.

Host microRNAs control both cellular processes and viral protein translation. Mandelboim et al. demonstrate synergism between host and viral microRNAs in downregulating the activatory ligand MICB, which facilitates immune evasion.

Allergies to nickel are the most frequent cause of contact hypersensitivity in industrialized countries. Goebeler and co-workers show that nickel induces an inflammatory response via direct activation of human Toll-like receptor 4.

Activation-induced cytidine deaminase triggers somatic hypermutation and immunoglobulin class switching. Mills and colleagues show that it can also cause widespread mutations outside the immunoglobulin heavy-chain locus.

Fish lack immunoglobulin A, which suggests that they lack specialized mucosal antibodies. Sunyer and colleagues show that immunoglobulin T fulfills this mucosal antibody function and engenders protection against gut parasites.

Immunoglobulin class-switch recombination can be induced by the secreted factors BAFF and APRIL. Cerutti and colleagues show that the receptor TACI conveys such signals via the adaptor MyD88 to induce class-switch recombination.

Type 1 regulatory T cells control autoinflammatory diseases. In two linked papers, groups led by Kuchroo and Quintana demonstrate the role of the aryl hydrocarbon receptor in the differentiation of these cells.

Type 1 regulatory T cells control autoinflammatory diseases. In two linked papers, groups led by Kuchroo and Quintana demonstrate the role of the aryl hydrocarbon receptor in the differentiation of these cells.

CD46 is best known as a regulator of complement function. Kemper et al. show that CD46 can switch inflammatory T cells into a regulatory mode and demonstrate the molecular details of this process.