Single-cell RNA sequencing reveals heterogeneous immune landscape of tumor infiltrated immune cell population in B cell deficiency against glioblastoma

Abstract The distinct immune landscape of glioblastoma (GBM) from other cancer is an obstacle to GBM treatment. To overcome the limited efficacy of GBM therapy, identifying the interaction between the tumor and infiltrated immune cells is needed. The function of B cells against tumors is recently focused on to understand tumor microenvironments. However, there are still few studies on the function of B cells in glioblastoma. Here, we identify tumor infiltrated immune cell population in B cell deficient mouse GBM by landscape analysis against glioblastoma. Using single-cell transcriptome analysis, we find that the frequency of tumor infiltrated immune cells including T cells and monocyte/macrophage is changed by the absence of B cells in mouse GBM. The frequency of effector CD8 and CD4 T cells decreases in B cell deficient mice. Also, expression of the cytotoxic signature protein is downregulated in tumor infiltrated T cells which are known to play an important role in tumor cell killing. In the case of tumor infiltrated macrophage and microglia, expression of M2 signature increased in B cell deficient GBM which can lead immunosuppressive tumor microenvironment. This study reveals changes in the immune cell landscape according to the presence or absence of B cells and shows how B cells contribute to antitumor immunity through immune interaction.