CCR6-Dependent Positioning of Memory B Cells Is Essential for Their Ability To Mount a Recall Response to Antigen

Chemokine-dependent localization of specific B cell subsets within the immune microarchitecture is essential to insure successful cognate interactions. While cognate interactions between T cells and memory B cells (B(mem))() are essential for the secondary humoral immune responses, the chemokine response patterns of B(mem) cells are largely unknown. In contrast to naïve B cells, this study shows that antigen-specific B(mem) cells have heightened expression of CCR6 and a selective chemotactic response to the CCR6 ligand, CCL20. While CCR6 appears be non-essential for the initial clonal expansion and maintenance of B(mem), CCR6 is essential for the ability of B(mem) to respond to a recall response to their cognate antigen. This dependency was deemed intrinsic by studies in CCR6-deficient mice and in bone-marrow chimeric mice where CCR6 deficiency was limited to the B cell lineage. Finally, the mis-positioning of CCR6-deficient B(mem) was revealed by immunohistological analysis with an altered distribution of CCR6-deficient B(mem) from the marginal and perifollicular to the follicular/germinal center area

The Heterogeneity of Ly6C(hi) Monocytes Controls Their Differentiation into iNOS(+) Macrophages or Monocyte-Derived Dendritic Cells

P.G. is a CNRS investigator. S.M. is funded by King’s Overseas Research Studentships. The research was supported by the MRC (MR/K01241X/1), BBSRC (BB/M029735/1), and King’s Health Partners. We thank Dr. Loredana Saveanu, Prof. Caetano Reis e Sousa, and Dr. Julie Helft for reagents and insightful discussions. All flow cytometry work was performed within the NIHR Biomedical Research Centre based at Guy’s and St. Thomas’ NHS Foundation Trust and King’s College London; we especially thank Prabhjoat Singh Chana for help at the facility and Nedyalko Petrov for assistance with t-SNE analysis. We would like to thank Matthew Arno and Erick Nasser at the Genomics Centre of King’s College London for performing the microarray experiments and providing technical support. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, or the Department of Health