[HTML][HTML] Fibroblastic reticular cells from lymph nodes attenuate T cell expansion by producing nitric oxide

S Siegert, HY Huang, CY Yang, L Scarpellino, L Carrie… - PloS one, 2011 - journals.plos.org
S Siegert, HY Huang, CY Yang, L Scarpellino, L Carrie, S Essex, PJ Nelson
PloS one, 2011journals.plos.org
Adaptive immune responses are initiated when T cells encounter antigen on dendritic cells
(DC) in T zones of secondary lymphoid organs. T zones contain a 3-dimensional scaffold of
fibroblastic reticular cells (FRC) but currently it is unclear how FRC influence T cell
activation. Here we report that FRC lines and ex vivo FRC inhibit T cell proliferation but not
differentiation. FRC share this feature with fibroblasts from non-lymphoid tissues as well as
mesenchymal stromal cells. We identified FRC as strong source of nitric oxide (NO) thereby …
Adaptive immune responses are initiated when T cells encounter antigen on dendritic cells (DC) in T zones of secondary lymphoid organs. T zones contain a 3-dimensional scaffold of fibroblastic reticular cells (FRC) but currently it is unclear how FRC influence T cell activation. Here we report that FRC lines and ex vivo FRC inhibit T cell proliferation but not differentiation. FRC share this feature with fibroblasts from non-lymphoid tissues as well as mesenchymal stromal cells. We identified FRC as strong source of nitric oxide (NO) thereby directly dampening T cell expansion as well as reducing the T cell priming capacity of DC. The expression of inducible nitric oxide synthase (iNOS) was up-regulated in a subset of FRC by both DC-signals as well as interferon-γ produced by primed CD8+ T cells. Importantly, iNOS expression was induced during viral infection in vivo in both LN FRC and DC. As a consequence, the primary T cell response was found to be exaggerated in Inos−/− mice. Our findings highlight that in addition to their established positive roles in T cell responses FRC and DC cooperate in a negative feedback loop to attenuate T cell expansion during acute inflammation.
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