We have recently demonstrated that LAG-3 (CD223), a CD4 homologue that binds to MHC class II with high affinity, is a key negative regulatory T (Treg) cell protein possessing both cell intrinsic and extrinsic activity. It is required for maximal Treg function and for the control of CD4+ and CD8+ T cell homeostasis. Remarkably, ectopic expression of LAG-3 alone can confer regulatory activity. Multiple experiments have shown that a unique 'KIEELE'motif in the LAG-3 cytoplasmic domain is essential for its function. Finally, we have shown that LAG-3 is efficiently cleaved from the cell surface within the membrane proximal connecting peptide. Despite the significant progress, important questions remain that will be addressed in the following Aims:
Specific Aim 1 : Does LAG-3 play a key role in controlling inflammatory reactions and autoimmunity? Even though we have shown that LAG-3 is required to control T cell function, no significant inflammatory reactions or autoimmunity are seen in LAG-3 -/- mice. We hypothesized that LAG-3 may only be important during an inflammatory or autoimmune disease. Our preliminary data support this view as IBD appears to be accelerated with LAG-3 -/- T cells and autoimmunity significantly enhanced in models of T1D and EAE. Here we will determine the mechanism behind this enhanced disease by analyzing LAG-3 -/- Teff and Treg function.
Specific Aim 2 : How is the intrinsic regulatory activity of LAG-3 released by T cells? We have recently shown that the metalloprotease-mediated cleavage of LAG-3 significantly modulates its regulatory activity. We hypothesize that LAG-3 cleavage is required to permit normal T cell proliferation and function. This will be assessed using shRNA mediated knockdown of ADAM10 and ADAM17, T cells from ADAM10fl/fl/ADAM17fl/fl/CreERT2 mice, and analysis of a knock-in mouse expressing non-cleavable LAG-3.
Specific Aim 3 : What is the mechanism of intrinsic LAG-3 activity in T cells? How LAG-3 works is an important question that remains unresolved. The co-receptor dependence of LAG-3 function has led us to hypothesize that LAG-3 interferes with coreceptor (and/or TCR) function on CD4* and CDS* T cells. (A) We will assess if the disruption of phosphorylation events by LAG-3 is restricted or global using multiplexed, reverse-phase protein lysate (RPPL) microarrays. We will also determine is LAG-3 modulates p56/c/
|Turnis, Meghan E; Andrews, Lawrence P; Vignali, Dario A A (2015) Inhibitory receptors as targets for cancer immunotherapy. Eur J Immunol 45:1892-905|
|Sawant, Deepali V; Hamilton, Kristia; Vignali, Dario A A (2015) Interleukin-35: Expanding Its Job Profile. J Interferon Cytokine Res 35:499-512|
|Sakaguchi, Shimon; Vignali, Dario A A; Rudensky, Alexander Y et al. (2013) The plasticity and stability of regulatory T cells. Nat Rev Immunol 13:461-7|
|Herold, Kevan C; Vignali, Dario A A; Cooke, Anne et al. (2013) Type 1 diabetes: translating mechanistic observations into effective clinical outcomes. Nat Rev Immunol 13:243-56|
|Delgoffe, Greg M; Woo, Seng-Ryong; Turnis, Meghan E et al. (2013) Stability and function of regulatory T cells is maintained by a neuropilin-1-semaphorin-4a axis. Nature 501:252-6|
|Delmastro, Meghan M; Styche, Alexis J; Trucco, Massimo M et al. (2012) Modulation of redox balance leaves murine diabetogenic TH1 T cells ""LAG-3-ing"" behind. Diabetes 61:1760-8|
|Do, Jeong-su; Valujskikh, Anna; Vignali, Dario A A et al. (2012) Unexpected role for MHC II-peptide complexes in shaping CD8 T-cell expansion and differentiation in vivo. Proc Natl Acad Sci U S A 109:12698-703|
|Gravano, David M; Vignali, Dario A A (2012) The battle against immunopathology: infectious tolerance mediated by regulatory T cells. Cell Mol Life Sci 69:1997-2008|
|Wang, X; Szymczak-Workman, A L; Gravano, D M et al. (2012) Preferential control of induced regulatory T cell homeostasis via a Bim/Bcl-2 axis. Cell Death Dis 3:e270|
|Woo, Seng-Ryong; Turnis, Meghan E; Goldberg, Monica V et al. (2012) Immune inhibitory molecules LAG-3 and PD-1 synergistically regulate T-cell function to promote tumoral immune escape. Cancer Res 72:917-27|
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