Bispecific Antibody PD-L1 x CD3 Boosts the Anti-Tumor Potency of the Expanded Vγ2Vδ2 T Cells

Abstract

Vγ2Vδ2 T cell-based immunotherapy has benefited some patients in clinical trials, but the overall efficacy is low for solid tumor patients. In this study, a bispecific antibody against both PD-L1 and CD3 (PD-L1 x CD3), Y111, could efficiently bridge T cells and PD-L1 expressing tumor cells. The Y111 prompted fresh CD8+ T cell-mediated lysis of H358 cells, but spared this effect on the fresh Vδ2+ T cells enriched from the same donors, which suggested that Y111 could bypass the anti-tumor capacity of the fresh Vγ2Vδ2 T cells. As the adoptive transfer of the expanded Vγ2Vδ2 T cells was approved to be safe and well-tolerated in clinical trials, we hypothesized that the combination of the expanded Vγ2Vδ2 T cells with the Y111 would provide an alternative approach of immunotherapy. Y111 induced the activation of the expanded Vγ2Vδ2 T cells in a dose-dependent fashion in the presence of PD-L1 positive tumor cells. Moreover, Y111 increased the cytotoxicity of the expanded Vγ2Vδ2 T cells against various NSCLC-derived tumor cell lines with the releases of granzyme B, IFNγ, and TNFα in vitro. Meanwhile, the adoptive transferred Vγ2Vδ2 T cells together with the Y111 inhibited the growth of the established xenografts in NPG mice. Taken together, our data suggested a clinical potential for the adoptive transferring the Vγ2Vδ2 T cells with the Y111 to treat PD-L1 positive solid tumors.

Vγ2 x PD-L1, a Bispecific Antibody Targeting Both the Vγ2 TCR and PD-L1, Improves the Anti-Tumor Response of Vγ2Vδ2 T Cell

“…The mean EC 50 values for Vg2 x PD-L1 binding to CHO-PD-L1, SKOV3, and H1975 were 1.444 nM, 0.594 nM, and 1.687 nM, respectively (Figure 1B, Figure 2). Both Vg2 x PD-L1 bsAb and PD-L1 mAb had a similar affinity to the cellular surface PD-L1 (Figure 1B), due to these two antibodies having the same variable regions for PD-L1 binding (23). Furthermore, we determined the PD-L1 expression scores for a series of target tumor cells using Vg2 x PD-L1 bsAb, which confirmed that Vg2 x PD-L1 exhibited potent affinity toward tumor cells with variable PD-L1 expression levels (Supplementary Figure 2).…”

“…The bsAbs, including Vg2 x PD-L1 and Vg2 x Null, were generated similarly to Y111 described previously by Yang et al (23). Briefly, the expression plasmids for Vg2 x PD-L1 and Vg2 x Null were synthesized and verified by sequencing in AuGCT Biotech (Wuhan, China).…”

“…Frozen or fresh human peripheral blood mononuclear cells (PBMCs) were obtained from LeiDeBio (Guangzhou, China) or Milestone (Shanghai, China). The ex vivo expansion protocol was described previously (23,25). Briefly, PBMCs were cultured in RPMI 1640 medium (Gibco, New York, USA) supplemented with 10% FBS (Excell, Clearwater, USA), at 2×10 6 cells/mL with the stimulation of 2.5 mM Zoledronic Acid (Sigma Aldrich, Darmstadt, Germany) and 1000 IU/mL IL2 (Sihuan Pharma, Beijing, China) for 10-14 days.…”

γδ T Cell–Based Adoptive Cell Therapies Against Solid Epithelial Tumors

“…Programmed cell death 1 ligand-targeted bispecific antibodies have also shown activation of Vγ9Vδ2 T cells, leading to tumor growth inhibition in vivo. 40 γδ T cells can also serve as vessels for chimeric antigen receptors (CARs) and TCRs. For example, an anti-chondroitinsulfate-proteoglycan 4 CAR showed equivalent tumor activity, yet less cytokine release than αβ T cells in an in vitro setting, suggesting a safer alternative to conventional engineered T cells against melanoma cell lines.…”

“…Programmed cell death 1 ligand–targeted bispecific antibodies have also shown activation of Vγ9Vδ2 T cells, leading to tumor growth inhibition in vivo. 40 …”