The lymph node stromal laminin α5 shapes alloimmunity
Lushen Li, … , Reza Abdi, Jonathan S. Bromberg
Lushen Li, … , Reza Abdi, Jonathan S. Bromberg
Published February 4, 2020
Citation Information: J Clin Invest. 2020;130(5):2602-2619. https://doi.org/10.1172/JCI135099.
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Research Article Immunology

The lymph node stromal laminin α5 shapes alloimmunity

Abstract

Lymph node stromal cells (LNSCs) regulate immunity through constructing lymphocyte niches. LNSC-produced laminin α5 (Lama5) regulates CD4+ T cells but the underlying mechanisms of its functions are poorly understood. Here we show that depleting Lama5 in LNSCs resulted in decreased Lama5 protein in the LN cortical ridge (CR) and around high endothelial venules (HEVs). Lama5 depletion affected LN structure with increased HEVs, upregulated chemokines, and cell adhesion molecules, and led to greater numbers of Tregs in the T cell zone. Mouse and human T cell transendothelial migration and T cell entry into LNs were suppressed by Lama5 through the receptors α6 integrin and α-dystroglycan. During immune responses and allograft transplantation, depleting Lama5 promoted antigen-specific CD4+ T cell entry into the CR through HEVs, suppressed T cell activation, and altered T cell differentiation to suppressive regulatory phenotypes. Enhanced allograft acceptance resulted from depleting Lama5 or blockade of T cell Lama5 receptors. Lama5 and Lama4/Lama5 ratios in allografts were associated with the rejection severity. Overall, our results demonstrated that stromal Lama5 regulated immune responses through altering LN structures and T cell behaviors. This study delineated a stromal Lama5–T cell receptor axis that can be targeted for immune tolerance modulation.

Authors

Lushen Li, Marina W. Shirkey, Tianshu Zhang, Yanbao Xiong, Wenji Piao, Vikas Saxena, Christina Paluskievicz, Young Lee, Nicholas Toney, Benjamin M. Cerel, Qinshan Li, Thomas Simon, Kyle D. Smith, Keli L. Hippen, Bruce R. Blazar, Reza Abdi, Jonathan S. Bromberg

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Figure 6

Lama5 regulates CD4+ T cell and Treg entry into LNs via αDG and α6 integrin.

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Lama5 regulates CD4+ T cell and Treg entry into LNs via αDG and α6 integ...
(A) CFSE-labeled iTregs (2 × 106) and 2 × 106 eFluor 670–labeled CD4+ cells transferred i.v. to Lama5-KO or WT mice. After 16 hours, LNs were stained for ER-TR7 and with DAPI and analyzed for the transferred cells. Left panels: Representative whole-section images (original magnification, ×20); arrowheads indicate HEVs. Scale bars: 200 μm (left) and 50 μm (right). Right panels: Quantification of naive CD4+ T cells and iTregs in the CR and HEVs (n = 30). (B and C) T cells pretreated with anti-αDG (2.5 μg mAb/106 cells, isotype IgM) or anti–α6 integrin (itg) (5 μg mAb/106 cells, isotype IgG) before transfer. After 16 hours, LNs were harvested for immunohistochemistry and flow cytometry. (B) Upper panels: Gating strategy. Lower panels: Number of transferred naive CD4+ T cells (eFluor 670+) and iTregs (CFSE+) per 1 × 106 total CD4+ T cells or total Foxp3+ cells (n = 6). (C) Upper panels: Representative scanning images (original magnification, ×20). LNs were stained for ER-TR7 and with DAPI and analyzed for transferred cells. Scale bar: 50 μm. Lower panels: Quantification of transferred naive CD4+ T cells (eFluor 670+) and iTregs (CFSE+) in the CR and HEVs (n = 30). Data (mean ± SEM) are from 3 independent experiments with 3 mice/group. For immunohistochemistry, 5 LNs/mouse, 3 sections/LN, and 3–5 fields/section. *P < 0.05; ***P < 0.001 by unpaired, 2-tailed Student’s t test.