Antibody-mediated activation of Vδ1 γδ T-cells for cancer immunotherapy
File(s)
Author(s)
Bhumbra, Shefali A.
Type
Thesis
Abstract
Cancer remains a global leading cause of death as current treatments are often ineffective and present with high relapse-rates and severe adverse reactions. Vδ1 γδ T-cells are gaining interest
as promising onco-immunotherapeutic targets due to their association with favourable prognoses in a myriad of malignancies. This thesis explores whether Vδ1-targeting bispecific engagers can improve immune responses against CD19+ haematological malignancies. Initial experiments investigated four Vδ1/CD19 bispecific engager formats, where only the BiTE format successfully enhanced Vδ1 function. The Vδ1/CD19 BiTE demonstrated specific binding to both Vδ1 TCR+ and CD19+ cells, resulting in TCR-downregulation, upregulation of T-cell activation markers 41BB, CD25 and CD107a, and enhanced cytotoxicity against CD19+ cell lines. Vδ1/CD19-treatment also increased PBMC cytotoxicity against CD19+ MEC-1 and primary CLL B-cells. To investigate mechanisms of healthy cell discrimination, differentially expressed ligands were identified from primary healthy B-cells, CLL B-cells and CD19+ cancer cell lines by RNA-analysis. Corresponding co-receptors to such ligands were identified using the literature. Following Vδ1/CD19 engager-treatment, naive PBMC-based Vδ1 T-cells increased expression of co-receptors NKG2D, CD96, DNAM-1, CD2, ICOS and PD-1 alongside CTLA-4 downregulation. Co-culture with MEC-1 cells enhanced granzyme B expression in PBMC-based Vδ1 T-cells and promoted effector-memory phenotypes. Blocking MEC-1 stress ligands reduced engager-treated Vδ1 cytotoxicity, though only under conditions of combined ligand-blockade, suggesting reduced susceptibility of these cells to immune evasion via downregulation of individual stress ligands. Engager treatment may prime naive Vδ1 T-cells for cytotoxicity by TCR-engagement but only engager-treated effector Vδ1 T-cells elicited a cytotoxic response when stimulated by plate-bound recombinant ligands, highlighting a potential lower threshold of activation for effector, over naive, Vδ1 T-cells. Findings also suggest effector Vδ1 T-cells modulate cytotoxicity through co-receptor signalling to discriminate between healthy and cancerous cells. Overall, the work presented in this thesis supports the continued investigation of Vδ1-targeting engagers as potential treatments for cancer.
as promising onco-immunotherapeutic targets due to their association with favourable prognoses in a myriad of malignancies. This thesis explores whether Vδ1-targeting bispecific engagers can improve immune responses against CD19+ haematological malignancies. Initial experiments investigated four Vδ1/CD19 bispecific engager formats, where only the BiTE format successfully enhanced Vδ1 function. The Vδ1/CD19 BiTE demonstrated specific binding to both Vδ1 TCR+ and CD19+ cells, resulting in TCR-downregulation, upregulation of T-cell activation markers 41BB, CD25 and CD107a, and enhanced cytotoxicity against CD19+ cell lines. Vδ1/CD19-treatment also increased PBMC cytotoxicity against CD19+ MEC-1 and primary CLL B-cells. To investigate mechanisms of healthy cell discrimination, differentially expressed ligands were identified from primary healthy B-cells, CLL B-cells and CD19+ cancer cell lines by RNA-analysis. Corresponding co-receptors to such ligands were identified using the literature. Following Vδ1/CD19 engager-treatment, naive PBMC-based Vδ1 T-cells increased expression of co-receptors NKG2D, CD96, DNAM-1, CD2, ICOS and PD-1 alongside CTLA-4 downregulation. Co-culture with MEC-1 cells enhanced granzyme B expression in PBMC-based Vδ1 T-cells and promoted effector-memory phenotypes. Blocking MEC-1 stress ligands reduced engager-treated Vδ1 cytotoxicity, though only under conditions of combined ligand-blockade, suggesting reduced susceptibility of these cells to immune evasion via downregulation of individual stress ligands. Engager treatment may prime naive Vδ1 T-cells for cytotoxicity by TCR-engagement but only engager-treated effector Vδ1 T-cells elicited a cytotoxic response when stimulated by plate-bound recombinant ligands, highlighting a potential lower threshold of activation for effector, over naive, Vδ1 T-cells. Findings also suggest effector Vδ1 T-cells modulate cytotoxicity through co-receptor signalling to discriminate between healthy and cancerous cells. Overall, the work presented in this thesis supports the continued investigation of Vδ1-targeting engagers as potential treatments for cancer.
Date Issued
2025-02-03
Date Awarded
01/09/2025
License URL
Advisor
Strid, Jessica
Good, Robert
Hutton, Andrew
Sponsor
Royal Commission for the Exhibition of 1851
Takeda Pharmaceuticals
Publisher Department
Department of Immunology and Inflammation
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)