Reversal of NK-Cell Exhaustion in Advanced Melanoma by Tim-3 Blockade

Abstract

The immunoregulatory protein T cell immunoglobulin- and mucin-domain-containing molecule-3 (Tim-3) mediates T cell exhaustion and contributes to the suppression of immune responses in both viral infections and tumors. Tim-3 blockade reverses the exhausted phenotype of CD4+ and CD8+ T cells in several chronic diseases including melanoma. Interestingly, natural killer (NK) cells constitutively express Tim-3; however, its role in modulating the function of these innate effector cells remains unclear, particularly in human disease. In this study, we compared the function of Tim-3 in NK cells from healthy donors and patients with metastatic melanoma. NK cells from the latter were functionally impaired/exhausted and Tim-3 blockade reversed this exhausted phenotype. Moreover, Tim-3 expression levels correlated with the stage of the disease and poor prognostic factors. These data indicate that Tim-3 can function as an NK cell exhaustion marker in advanced melanoma and supports the development of Tim-3-targeted therapies to restore antitumor immunity.

Blockade of LAG3 enhances responses of tumor-infiltrating T cells in mismatch repair-proficient liver metastases of colorectal cancer

“…TIL and PBMC from LM-CRC were labeled with 0.1 µM carboxyfluorescein diacetate succinimidyl ester (CFSE, Invitrogen); afterwards 10 5 TIL or PBMC were cultured in 200 µl complete medium in each well of a 96-well round-bottom culture plate and stimulated with anti-human CD3/CD28 dynabeads (Gibco-Life Technologies AS, Norway) at a cell: bead ratio of 10:1, in the presence or absence of 10 μg/ml antagonistic monoclonal antibodies against human PD-L1 (clone 5H1, kindly provided by Dr. Haidong Dong, Mayo Clinic College of Medicine, 59 ) TIM3 (clone F38-2E2, Biolegend, San Diego, USA, 60 , 61 ) LAG3 (clone 17B4, AdipoGen, Liestal, Switzerland 62 ) or CTLA4 (clone BNI3, Beckman Coulter, Marseille, France, 63 ) or isotype-matched control antibodies (mIgG1 and mIgG2 a, Biolegend, London, UK). In preliminary experiments a cell: bead ratio of 10:1 was established to provide sub-optimal stimulation of T cell proliferation.…”

Blocking monoclonal antibodies of TIM proteins as orchestrators of anti-tumor immune response

“…62 Additionally, TIM-3 is highly expressed on effector immune cells such as T cells and NK cells, and serves as an exhaustion marker for T cells and NK cells. 45,46,53 Together, these results suggest that the manipulation of TIMs functions by mAbs is a promising and powerful strategy to initiate or amplify an existing immune response against tumors (Fig. 2).…”

“…Indeed, anti-TIMs mAbs have been shown to improve the performance of APCs by enhancing secretion of cytokines and antigen presentation to T cells, 44,62 recovery of exhausting T cell, and NK cells. 45,46,53 Monotherapies with anti-TIMs mAbs have been evaluated in experimental mouse tumor models, and anti-TIMs mAbs have also shown preclinical synergistic effects with several forms of cancer vaccines and chemotherapy (Tables 1-3). Another interesting area that is still largely unexplored is the combination of anti-TIMs mAbs with adoptive transfer of T cells.…”

“…2E2 and AF2365 clones were effective to enhance proliferation and cytotoxic activities of NK cells, and to expand antigen-specific CD8 C T cells with increased IFN-g production when combined with peptide vaccination of melanoma. 45,46,53 ATIK2a clone, another mAb that targets human TIM-3, was found to induce antibody-dependent cell-mediated cytotoxicity (ADCC), and was effective in eradicating TIM-3-expressing leukemia stem cells in an acute myeloid leukemia model. 54,55 On the other hand, 334823 and 344801 clones may act as antagonist mAb because the cross-linking of these mAb with its targets on NK cells has suppressed NK cell-mediated cytotoxicity in in vitro experiments.…”

Antibody-Mediated Phosphatidylserine Blockade Enhances the Antitumor Responses to CTLA-4 and PD-1 Antibodies in Melanoma

“…14, 15), lymphocyte-activation gene 3 (LAG3; refs. 16,17), and Tim3 (18,19) and for agonists that activate immune stimulatory pathways, such as 4-1BB (CD-137; refs. 20, 21), OX40 (22,23), inducible T-cell costimulator (24), and GITR.…”