苔藓抑素通过克服胞啃作用介导的抗原丢失增强 CD20 CAR-T 治疗 B 细胞淋巴瘤的疗效

CD20 antigen expression and trogocytosis-mediated membrane transfer were assessed by flow cytometry and immunofluorescence following co culture of CD20 CAR T cells with Raji or BALL 1 cells. Trogocytosis positive (Trog ) CAR T cell cytotoxicity and fratricide by fresh CAR T cells were evaluated by ELISA. Proteomic profiling compared metabolic features of Trog and Trog CAR T cells. Using flow sorted BALL 1 subsets with differential CD20 expression (CD20 low , CD20 mid , CD20 hi ), we examined how antigen density affects CAR T persistence and killing. Finally, Bryostatin mediated CD20 upregulation and its therapeutic impact on CAR T efficacy were tested in vitro and in a murine subcutaneous lymphoma model.

Upon contact with Raji or BALL-1 cells, CD20 CAR T cells underwent trogocytosis, leading to marked loss of tumor cell CD20 and impaired cytotoxicity of trogocytosis positive (Trog ) CAR T cells, which also became susceptible to fratricide. CD20 antigen density positively correlated with CAR T killing efficacy. Proteomic analysis revealed that Trog CAR T cells exhibited enriched activity in ribosome biogenesis, mRNA surveillance, and RNA catalysis, suggesting elevated protein synthesis alongside exhaustion features. Key MEK/ERK related transcription factors (c JUN, TCF7) linked to T cell activation were downregulated in Trog cells. In both in vitro and mouse lymphoma models, Bryostatin potentiated CD20 CAR T mediated tumor suppression. Mechanistically, bryostatin upregulated CD20 expression in tumor cells via the MEK/ERK pathway and enhanced c JUN/TCF7 levels in CAR T cells, promoting their tumor infiltration.

Bryostatin enhances CD20 CAR T efficacy by counteracting trogocytosis driven antigen loss and upregulating CD20 expression, providing a promising strategy to overcome antigen escape in lymphoma therapy.