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In this Perspective, Alon and colleagues discuss how insights into immune cell trafficking during pneumotropic influenza virus infections may inform our understanding of immune cell recruitment to the respiratory tract in patients with coronavirus disease 2019 (COVID-19). Moreover, they examine the emerging knowledge of vascular pathologies beyond the lung caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
A number of T cell-intrinsic peripheral tolerance mechanisms (quiescence, ignorance, anergy, exhaustion, senescence and cell death) restrain autoimmunity and overactive immune responses. Here, the authors provide an integrated perspective of peripheral T cell tolerance by comparing the molecular mechanisms that govern these checkpoints and discussing their role in T cell tolerance and fate regulation.
How does the discovery of SARS-CoV-2 cross-reactive T cells in unexposed individuals change our understanding of the COVID-19 pandemic? In this Perspective, the authors provide a thought experiment to explain why the discovery of cross-reactive T cells may affect disease severity in individuals, but is unlikely to change our estimate of the herd immunity threshold.
Why does the human genome encode more than 300 potential immune inhibitory receptors? Here, the authors propose a categorization of inhibitory receptors — as threshold receptors and negative feedback receptors — that reflects their distinct functions in immune regulation, illustrated using mathematical modelling. This categorization may be useful for the therapeutic targeting of inhibitory receptors.
Recombinant granulocyte–macrophage colony-stimulating factor (GM-CSF) as well as antibodies targeted at GM-CSF or its receptor are being tested in clinical trials for coronavirus disease 2019 (COVID-19). This Perspective introduces the pleiotropic functions of GM-CSF and explores the rationale behind these different approaches.
Why are males more susceptible to severe COVID-19 than females? In this Perspective, Sabra Klein and colleagues consider the sex differences in the immune system that may contribute to this sex bias.
The authors describe how the naive T cell compartment is built across a lifetime. They propose that functional diversity among naive T cells is linked to when they were created. Naive T cells adapt to meet changes in the external environment at different stages of life, persist into adulthood and contribute to the T cell compartment in adults.
