BiTE-Secreting CAR-γδT as a Dual Targeting Strategy for the Treatment of Solid Tumors

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Human Leukocyte Antigen-G (HLA-G) is an immune checkpoint protein and tumor antigen targeted in CAR-NK therapies.
• Co-expression of PD-L1 and HLA-G, and PD-L1 upregulation post-therapy, can limit HLA-G-CAR efficacy.
• Gamma-delta T (γδT) cells offer MHC-independent cytotoxicity and allogeneic potential for adoptive immunotherapy.

Purpose of the Study:

• To develop a multi-specific CAR therapy simultaneously targeting HLA-G and PD-L1.
• To utilize nanobodies for flexible CAR engineering and novel epitope recognition.
• To evaluate the efficacy and safety of a novel nanobody-based CAR construct in γδT cells.

Main Methods:

• Engineered Vδ2 γδT cells with an mRNA-driven, nanobody-based HLA-G-CAR and a secreted PD-L1/CD3ε Bispecific T-cell engager (BiTE) construct (Nb-CAR.BiTE).
• In vitro and in vivo experiments to assess tumor elimination and immune cell recruitment.
• Evaluation of tumor site targeting and systemic toxicity.

Main Results:

• Nb-CAR.BiTE-γδT cells effectively eliminated solid tumors expressing PD-L1 and/or HLA-G.
• The secreted PD-L1/CD3ε Nb-BiTE redirected Nb-CAR-γδT cells and recruited bystander T cells against PD-L1-expressing tumors.
• Nb-CAR.BiTE localized to tumor sites with no apparent systemic toxicity.

Conclusions:

• Simultaneous targeting of HLA-G and PD-L1 via Nb-CAR.BiTE-γδT cells is a promising strategy for solid tumor treatment.
• The secreted BiTE enhances therapeutic efficacy by engaging both engineered and endogenous T cells.
• This approach offers a potent and potentially safer immunotherapy for solid tumors.