Development of AptCD4-LNT for selective mobilization and activation CD4+ T cells to enhance anti-tumor immunity in triple-negative breast cancer

CD8+ T cells are well-established primary effectors in anti-tumor immunity, but increasing evidence underscores the critical and multifaceted role of CD4+ T cells, which can function both as helper cells and direct tumor killers. However, the clinical potential of CD4+ T cells has been limited by poor tumor infiltration and the challenges posed by an immunosuppressive tumor microenvironment. To address these limitations, we developed a CD4 aptamer-engineered liquid nitrogen-treated cancer cell system (AptCD4-LNT) designed to selectively activate and recruit CD4+ T cells for improved anti-tumor immunity. This system leverages the CD4 aptamer's specificity for CD4+ T cells and the homing properties of LNT cells to drive targeted infiltration and activation of CD4+ T within the tumor microenvironment. Activated CD4+ T cells, in turn, enhance the infiltration and activity of NK cells, B cells, and dendritic cells, reshaping the immune landscape and potentiating anti-tumor responses in triple-negative breast cancer. Our findings highlight the pivotal role of CD4+ T cells in TNBC immunotherapy and present a promising strategy for advancing CD4-targeted treatments in clinical settings. Overall design: After receiving AptCD4-LNT administration every 3 days with a dose of 5 × 10^6 cells, 4 × 10^6 cells, and 3 × 10^6 cells, sequentially, triple negative breast cancer (4T1) bearing mice were sacrificed at 9 days, and tumor tissues were obtained for scRNA-Seq. The untreated mice bearing triple negative breast cancer received PBS as the control.