CELL INTELLIGENCE · 肿瘤细胞治疗研究

The outcome of patients with acute myeloid leukemia remains poor, and immunotherapy has the potential to improve this. T cells expressing chimeric antigen receptors or bispecific T-cell engagers targeting CD123 are actively being explored in preclinical and/or early phase clinical studies.

We have shown that T cells expressing CD123-specific bispecific T-cell engagers (CD123. ENG T cells) have anti-acute myeloid leukemia activity.

However, like chimeric antigen receptor T cells, their effector function diminishes rapidly once they are repeatedly exposed to antigen-positive target cells.

Here we sought to improve the effector function of CD123. ENG T cells by expressing inducible co-stimulatory molecules consisting of MyD88 and CD40 (iMC), MyD88 (iM), or CD40 (iC), which are activated by a chemical inducer of dimerization. CD123. ENG T cells expressing iMC, iM, or iC maintained their antigen specificity in the presence of a chemical inducer of dimerization, as judged by cytokine production (interferon-γ, interleukin-2) and their cytolytic activity.

In repeat stimulation assays, activating iMC and iM, in contrast to iC, enabled CD123. ENG T cells to secrete cytokines, expand, and kill CD123-positive target cells repeatedly. Activating iMC in CD123. ENG T cells consistently improved antitumor activity in an acute myeloid leukemia xenograft model. This translated into a significant survival advantage in comparison to that of mice that received CD123. ENG or CD123. ENG. iC T cells. In contrast, activation of only iM in CD123. ENG T cells resulted in donor-dependent antitumor activity.

Our work highlights the need for both toll-like receptor pathway activation via MyD88 and provision of co-stimulation via CD40 to consistently enhance the antitumor activity of CD123. ENG T cells.