Macrophages are associated with many human diseases but are challenging to study in vivo. Here, Ginhoux and colleagues discuss how iMacs — macrophages generated from induced pluripotent stem (iPS) cells — can enable disease modelling, including through the use of patient-derived iPS cells and 3D organoid co-culture systems. Ultimately, these iMac-based approaches can improve our understanding of macrophage biology in both health and disease.

Technological advances in cellular and molecular immunology are providing unprecedented new insights into evolutionary immunology. This Perspective highlights new insights into the immune systems of different vertebrate species and discusses emerging general principles of immune system function.

Macrophages are innate immune sentinels providing frontline defence against infection. This Review describes the inducible mechanisms used by macrophages to kill bacterial pathogens and/or inhibit their growth and outlines how this knowledge might be exploited in the design of host-directed therapies.

For effective central T cell tolerance, developing thymocytes must encounter a diverse range of self-antigens presented by various thymic cells. Here, the authors describe how medullary thymic epithelial cells, dendritic cells and B cells are uniquely adapted through promiscuous gene expression, strategic positioning and inflammatory signals, which shape the peptide–MHC ligandomes and extend self-antigen visibility in the thymic microenvironment.