[HTML][HTML] Bone marrow is the preferred site of memory CD4+ T cell proliferation during recovery from sepsis

T Skirecki, P Swacha, G Hoser, J Golab, D Nowis… - JCI insight, 2020 - ncbi.nlm.nih.gov
T Skirecki, P Swacha, G Hoser, J Golab, D Nowis, E Kozłowska
JCI insight, 2020ncbi.nlm.nih.gov
Sepsis survivors suffer from increased vulnerability to infections, and lymphopenia
presumably contributes to this problem. The mechanisms of the recovery of memory CD4+ T
cells after sepsis remain elusive. We used the cecal ligation and puncture mouse model of
sepsis to study the restoration of the memory CD4+ T cells during recovery from sepsis.
Then, adoptive transfer of antigen-specific naive CD4+ T cells followed by immunization and
BrdU labeling were performed to trace the proliferation and migration of memory CD4+ T …
Abstract
Sepsis survivors suffer from increased vulnerability to infections, and lymphopenia presumably contributes to this problem. The mechanisms of the recovery of memory CD4+ T cells after sepsis remain elusive. We used the cecal ligation and puncture mouse model of sepsis to study the restoration of the memory CD4+ T cells during recovery from sepsis. Then, adoptive transfer of antigen-specific naive CD4+ T cells followed by immunization and BrdU labeling were performed to trace the proliferation and migration of memory CD4+ T cells. We revealed that the bone marrow (BM) is the primary site of CD4+ memory T cell homing and proliferation after sepsis-induced lymphopenia. Of interest, BM CD4+ T cells had a higher basal proliferation rate in comparison with splenic T cells. These cells also show features of resident memory T cells yet have the capacity to migrate outside the BM niche and engraft secondary lymphoid organs. The BM niche also sustains viability and functionality of CD4+ T cells. We also identified IL-7 as the major inducer of proliferation of the BM memory CD4+ T cells and showed that recombinant IL-7 improves the recovery of these cells. Taken together, we provide data on the mechanism and location of memory CD4+ T cell proliferation during recovery from septic lymphopenia, which are of relevance in studying immunostimulatory therapies in sepsis.
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