Enhanced Cell Division Is Required for the Generation of Memory CD4 T Cells to Migrate Into Their Proper Location

• Main Authors: Jana Sarkander, Shintaro Hojyo, Mathias Mursell, Yuzuru Yamasaki, Tsung-Yen Wu, Damon J. Tumes, Kosuke Miyauchi, Cam Loan Tran, Jinfang Zhu, Max Löhning, Andreas Hutloff, Mir-Farzin Mashreghi, Masato Kubo, Andreas Radbruch, Koji Tokoyoda
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2020-01-01
• Series: Frontiers in Immunology
• Subjects: CD4 T cells; memory; bone marrow; cell division; migration
• Online Access: https://www.frontiersin.org/article/10.3389/fimmu.2019.03113/full

CD4 T cell memory is fundamental for long-lasting immunity and effective secondary responses following infection or vaccination. We have previously found that memory CD4 T cells specific for systemic antigens preferentially reside in the bone marrow (BM) and arise from splenic CD49b+T-bet+ CD4 T cells. However, how BM-homing memory precursors are generated during an immune reaction is unknown. We show here that BM memory precursors are generated via augmented rates of cell division throughout a primary immune response. Treatment with the cytostatic drug cyclophosphamide or blockade of the CD28/B7 co-stimulatory pathway at the beginning of the contraction phase abrogates the generation of BM memory precursors. We determine that, following a critical number of cell divisions, memory precursors downregulate CCR7 and upregulate IL-2Rβ, indicating that loss of CCR7 and gain of IL-2 signal are required for the migration of memory precursors toward the BM.