Lenalidomide boosts CD1d-Vδ2 bispecific antibody-engaged Vγ9Vδ2-T cell effector functions via CD28, Notch signaling and IL-2 release

BACKGROUND: Vγ9Vδ2-T cells form a conserved T-cell subset known for its potent intrinsic antitumor activity and versatility in recognizing diverse cancer types independently of the major histocompatibility complex. Previously, we reported the preclinical activity of a bispecific T-cell engager (bsTCE) specific for both CD1d and the Vδ2-TCR that engaged both Vγ9Vδ2-T and type 1 natural killer T cells to CD1d-expressing hematological malignancies, including multiple myeloma (MM) and acute myeloid leukemia (AML). Here, we evaluated whether various standard-of-care drugs for patients with MM and AML/myelodysplastic syndromes (MDS) affected the in vitro antitumor activity of CD1d-Vδ2 bsTCE-activated Vγ9Vδ2-T cells. METHODS: MM and AML/MDS standard-of-care drugs were tested for antagonistic, additive, or synergistic effects on CD1d-Vδ2 bsTCE-induced and Vγ9Vδ2-T cell-mediated tumor cell lysis. Based on observed synergy, the immunomodulatory drug (IMiD) lenalidomide was studied in more detail, exploring effects on Vγ9Vδ2-T cell proliferation, phenotype, cytokine profile, and cytolytic activity, as well as its mechanism of action, using healthy donor peripheral blood mononuclear cells (PBMC) and MDS patient PBMC and bone marrow samples. RESULTS: 1-type cytokine secretion, and expansion. Stimulatory effects of lenalidomide on Vγ9Vδ2-T cell effector functions were mediated via enhanced intracellular CD28 phosphorylation, activation of Notch signaling, and interleukin-2 release. Importantly, lenalidomide facilitated otherwise absent proliferation of Vγ9Vδ2-T cells with oncolytic potential in response to CD1d-Vδ2 bsTCE exposure in MDS patient-derived bone marrow samples. CONCLUSION: Our findings provide a rationale to explore the combination of CD1d-Vδ2 bsTCE and the IMiD lenalidomide in patients with CD1d-expressing hematological malignancies.