Goswami and colleagues describe how lactylation of histone lysine residues regulates the transcriptome, metabolism and function of CD8⁺ T cells.

Poholek and colleagues show that, during allergic airway inflammation, the transcription factor Blimp-1 regulates CD4⁺T_H2 cell migration to the lung and define anatomical locations in mediastinal lymph nodes where IL-2 programming induces T_H2 cell polarization.

Dolatshahi and Wessel use an in silico modeling approach to predict maternal–fetal IgG transfer selectivity and efficiency in utero that is needed for neonate protection against pathogens.

In this Review, Sarah Cobey discusses how past exposures shape B cell responses to vaccinations with influenza and SARS-CoV-2.

Poholek and colleagues show that, during allergic airway inflammation, the transcription factor Blimp-1 regulates CD4⁺T_H2 cell migration to the lung and define anatomical locations in mediastinal lymph nodes where IL-2 programming induces T_H2 cell polarization.

Goswami and colleagues describe how lactylation of histone lysine residues regulates the transcriptome, metabolism and function of CD8⁺ T cells.

Some enhancers can limit their activities to specific spatial–temporal domains by enhancer suboptimization. Ou et al. find that classical dendritic cell (cDC) development depends on Irf8 suboptimization, which prevents unwanted IRF8 autoactivation in developing cDC2s while maximizing IRF8 expression in developed cDC1s.

Misharin, Sala and colleagues show that in patients with lung fibrosis after COVID-19, monocyte-derived alveolar macrophages activate an inflammatory and fibrotic program that was similar in patients with either resolving or progressing fibrosis.

This Comment discusses the explosion in innovative systems biology approaches in infectious disease studies. We outline the numerous challenges associated with these technologies from standardizing data science approaches to reproducibility of findings, as well as cost.