Journal roundup

SARS-CoV-2 variants have acquired mutations that enhance the virus pathogenicity and its escape from antibody neutralization. In this issue, Schulz et al. use flow cytometry and pseudovirus neutralization assays to demonstrate that the third vaccination with BNT162b effectively increases neutralizing serum antibodies against Delta and Omicron variants. In addition, most clinically approved antibodies failed to bind and neutralize the Omicron variant. However, two novel antibodies under preclinical development show promising neutralization potential against the Delta and Omicron variants of concern. This work also highlights using a flow cytometry-based binding assay for fast monitoring of serum and monoclonal antibodies against emerging SARS-CoV-2 variants of concern.

Long-term T-cell memory is principally maintained in lymphoid tissues and at the body surfaces. However, much of the current information on human T-cell memory is based on analyzing circulating T cells. Here, we studied human T cells obtained from blood, spleen, mesenteric lymph nodes and ileal mucosa (age range 5 days - 67 years) with flow cytometry and T-cell receptor sequencing. Our data indicate the lymph node to be the main reservoir of polyclonal naïve cells and resting memory cells capable of self-renewal. In contrast, nondividing but functionally active memory subsets dominate the spleen and the ileal mucosa. We also observed substantial differences of maturation patterns between CD4+ and CD8+ compartments. Along aging, the fraction of memory subsets increases with no apparent plateau. Our data provide a reference of the patterns of T-cell maturation in different tissues.