Nature Reviews Immunology最新文献

Macrophages are the primary host cell type for infection by Mycobacterium tuberculosis in vivo. Macrophages are also key immune effector cells that mediate the control of bacterial growth. However, the specific macrophage phenotypes that are required for optimal immune control of M. tuberculosis infection in vivo remain poorly defined. There are two distinct macrophage lineages in the lung, comprising embryonically derived, tissue-resident alveolar macrophages and recruited, blood monocyte-derived interstitial macrophages. Recent studies have shown that these lineages respond divergently to similar immune environments within the tuberculosis granuloma. Here, we discuss how the differing responses of macrophage lineages might affect the control or progression of tuberculosis disease. We suggest that the ability to reprogramme macrophage responses appropriately, through immunological or chemotherapeutic routes, could help to optimize vaccines and drug regimens for tuberculosis.

The cyclic GMP–AMP synthase (cGAS)–stimulator of interferon genes (STING) signalling pathway, which recognizes both pathogen DNA and host-derived DNA, has emerged as a crucial component of the innate immune system, having important roles in antimicrobial defence, inflammatory disease, ageing, autoimmunity and cancer. Recent work suggests that the regulation of cGAS–STING signalling is complex and sophisticated. In this Review, we describe recent insights from structural studies that have helped to elucidate the molecular mechanisms of the cGAS–STING signalling cascade and we discuss how the cGAS–STING pathway is regulated by both activating and inhibitory factors. Furthermore, we summarize the newly emerging understanding of crosstalk between cGAS–STING signalling and other signalling pathways and provide examples to highlight the wide variety of cellular processes in which cGAS–STING signalling is involved, including autophagy, metabolism, ageing, inflammation and tumorigenesis.

Despite its importance for generating and maintaining a healthy and broad T cell repertoire, the thymus is exquisitely sensitive to acute damage. Marked thymic involution occurs in response to stimuli as diverse as infection, stress, pregnancy, malnutrition, drug use and cytoreductive chemotherapy. However, the thymus also has a remarkable capacity for repair, although this regenerative capacity declines with age. Endogenous thymic regeneration is a crucial process that allows for the recovery of immune competence after acute damage and delay to this recovery can have important clinical effects. Until recently, the mechanisms that drive endogenous thymic regeneration were not well understood, but recent work in mice has revealed multiple distinct pathways of regeneration and the molecular mechanisms that trigger these pathways after damage. In this Review, we discuss the effects of different types of damage to the thymus, with a focus on an emerging body of work in mice that provides insight into the cellular and molecular mechanisms that regulate endogenous tissue regeneration in the thymus. We also highlight some of the clinical challenges that are presented by dysregulated thymic regeneration.

Cancers can avoid immune-mediated elimination by acquiring traits that disrupt antitumour immunity. These mechanisms of immune evasion are selected and reinforced during tumour evolution under immune pressure. Some immunogenic subclones are effectively eliminated by antitumour T cell responses (a process known as immunoediting), which results in a clonally selected tumour. Other cancer cells arise to resist immunoediting, which leads to a tumour that includes several distinct cancer cell populations (referred to as intratumour heterogeneity (ITH)). Tumours with high ITH are associated with poor patient outcomes and a lack of responsiveness to immune checkpoint blockade therapy. In this Review, we discuss the different ways that cancer cells evade the immune system and how these mechanisms impact immunoediting and tumour evolution. We also describe how subclonal antigen presentation in tumours with high ITH can result in immune evasion.