Progress

In this Progress article, Male summarizes our current understanding of the risks associated with SARS-CoV-2 infection in pregnancy. Importantly, the article highlights the now substantial body of evidence supporting the safety and efficacy of COVID-19 vaccination in pregnancy.

Hyperactivation of the complement system has been implicated in the pathology of COVID-19. Here the authors bring together the latest information on the role of complement in COVID-19 and progress in targeting complement components for treatment of severe disease.

Individuals with asymptomatic COVID-19 can transmit the virus and may be at risk of long-term disease. In this Progress article, Boyton and Altman present current insights into immune responses in asymptomatic SARS-CoV-2 infection and discuss the relevance of asymptomatic disease for public health strategies.

This Progress article provides an update on the COVID-19 vaccine effort in the light of ongoing vaccine efficacy studies and real-world data on vaccine effectiveness, including the impact of virus variants of concern and challenges for global deployment.

This Progress article brings us up to date on the role of inflammasomes in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19, describing how they may be activated during infection and contribute to the overexuberant inflammatory response in severe disease, and the efforts being taken to target them therapeutically.

This Progress article summarizes our current understanding of the immune mechanisms of protection induced by the available COVID-19 vaccines. The authors compare vaccine-induced antibody responses following one or two doses of different vaccines and consider the relative importance of neutralizing antibodies for vaccine-mediated protection against SARS-CoV-2.

As the world races to develop vaccines against SARS-CoV-2, Dai and Gao highlight which viral targets are best to include in a vaccine and how this impacts the induced immune response and, ultimately, the safety and efficacy of a vaccine.

In this Progress article, Wang and Colonna highlight a flurry of recent reports that have shaped our understanding of how environmental cues and clock genes regulate group 3 innate lymphoid cells. They consider the implications of these findings for intestinal immunity.

In this Progress article, Zeyu Chen and E. John Wherry summarize early reports of the T cell responses observed in patients with COVID-19, emphasizing how different immune response characteristics in different patients may reflect a spectrum of disease phenotypes.

This Progress article from Merad and Martin examines our current understanding of the excessive inflammatory responses seen in patients with severe COVID-19. The authors focus on the emerging pathological roles of monocytes and macrophages and discuss the inflammatory pathways that are currently being targeted in the clinic.

Freeman and colleagues draw our attention to the existence of different forms of PDL1 — cell bound and various extracellular forms. Recent studies show that PDL1 on exosomes can inhibit antitumour immune responses and may be a useful biomarker for the management of cancer immunotherapy.

The presence of nucleic acids in the cytosol alerts the cell to viral infection or damaged self. The oligoadenylate synthase (OAS) proteins and cyclic GMP–AMP synthase (cGAS) are enzymes that detect this danger and promote antiviral immunity. Recent structural studies reveal that these enzymes have a common mechanism of action and probably the same evolutionary origin.

The identification of NLRC5 as a transcriptional transactivator of MHC class I genes has shed light on the regulation of MHC class I expression. This Progress article summarizes the recent advances in the field and highlights some of the questions that still remain to be addressed.

Interleukin-9 (IL-9) has recently entered the limelight owing to the discovery that it can be produced by multiple T helper cell subsets. This Progress article updates us on the cellular sources, targets and immune functions of IL-9.

Recent studies have identified a new population of interleukin-22-producing cells in mucosal tissues that share features with both lymphoid-tissue inducer cells and natural killer cells. How are these three cell populations related and what might be the function of the new cell population?

Regulatory T (T_Reg) cells are crucial for immune homeostasis, and manipulation of their suppressive functions is a possible avenue for immunotherapy. Here, the authors discuss recent advances in our understanding of how the expression of forkhead box P3 (FOXP3), a T_Reg-cell-specifying transcription factor, is controlled at the molecular level.

Basophils, often regarded as a lesser relative to the mast cell, are now proving to have important, non-redundant roles in immune responses. This Progress article updates us on the latest studies that identify new roles for basophils in allergic reactions and immune regulation.

Antimicrobial proteins are an ancient mechanism of defence against pathogens at skin and mucosal surfaces. As discussed in this Progress article, new studies identify dynamic cross-regulation between cytokines and antimicrobial peptides, which contributes to immunity and homeostasis at these sites.

The TIM (T-cell immunoglobulin domain and mucin domain) proteins are emerging as important regulators of immune responses. The recent identification of TIM-protein expression by antigen-presenting cells and new TIM-protein ligands is revealing new roles for these proteins.

Recent research on MALT1 (mucosa-associated-lymphoid-tissue lymphoma-translocation gene 1), a protein essential for nuclear factor-κB (NF-κB) activation, has uncovered new mechanisms by which MALT1 can orchestrate intracellular signalling events. Here, Margot Thome highlights recent progress which characterizes how the protease and scaffolding functions of MALT1 modulate T-cell activation.