Volume 17 Issue 2, February 2016

Thymic selection shapes the repertoire of potentially autoreactive thymocytes that are allowed to mature. The expression pattern of self antigen seen by thymocytes determines the number and functional ability of autoreactive T cells.

Arteries are colonized by macrophages of multiple origins, derived prenatally from the yolk sac and during an early postnatal wave from the bone marrow. During sepsis, blood monocyte-derived macrophages transiently contribute to, but do not replace, resident arterial macrophages that largely self-renew in situ.

Viral infection of the mucosa induces a strong host innate immune response involving type I interferons and interferon-stimulated genes. New findings show that mechanical or pathogen-induced disruption of the mucus itself can also trigger 'hyper-early' innate responses independent of type I interferons and major sensing pathways of the innate immune system.

IL-33 has well-described roles in type 2 immune responses; however, the scope of its functions are rapidly widening. Martin and Martin review the latest knowledge on IL-33 as an alarmin, intracellular molecule and cytokine.

Murray reviews how immune cells integrate information about external essential amino acids supplies and transfer signals to growth and activation pathways that dictate cell function.

Sumolyation regulates wide-ranging biological processes, but its influence on innate immunity is unclear. Amigorena and colleagues show that sumoylation negatively regulates interferon-β expression and anti-viral immunity.

Mucosal surfaces often represent the first point of entry for pathogens. Paludan and colleagues demonstrate that disruption of the mucus itself can initiate a hyperacute innate immune response that precedes even the production of type I interferons.

Macrophages densely populate the arterial wall, yet their origin and homeostasis are poorly understood. Robbins and colleagues show that arterial macrophages arise from CX3CR1⁺ embryonic precursors and adult bone marrow–derived monocytes that colonize the tissue immediately after birth.

Group 3 innate lymphoid cells have low expression of the transcription factor GATA-3. Zhu and colleagues show that despite its low expression, GATA-3 is essential for the homeostasis, further maturation and effector function of lineage-committed group 3 innate lymphoid cells.

The function of group 3 innate lymphoid cells (ILC3 cells) is still being determined. Vivier and colleagues describe the development of ILC3 subsets and show that NCR⁺ ILC3 cells are not needed to control infection with Citrobacter rodentium in the presence of an intact T cell compartment.

CD4⁺ T cell tolerance can be enforced by various mechanisms. Jenkins and colleagues use mice with entirely intact polyclonal T cell repertoires to comprehensively define the mechanisms of self-tolerance.

A hallmark of systemic lupus erythematosus is the production of type I interferons in response to immunocomplexes containing self DNA from dead cells and DNA-specific IgG. Sanjuan and colleagues find that IgE specific for self DNA also exacerbates this disease.

Vaccination offers protection against infectious diseases, yet pre-existing criteria that predict vaccine efficacy or adverse events remain unknown. Hayday and colleagues identify cellular and molecular signatures in humans immunized with adjuvanted swine flu vaccine.