CXCL13-expressing CD4 ⁺ T cells coordinate the lymphocytes triad to promote the anti-tumor immunity in NSCLC

CD4+ T cells are indispensable for CD8+ T cells-mediated anti-tumor immunity, while little is known about how CD4+ T cells coordinate with other cells to promote CD8+ T cells activity. In this study, by coupling single-cell RNA sequencing (scRNA-seq) with multiplex immunohistochemistry staining (mIHC), CXCL13-expressing CD4+ T cells were explored to recruit CXCR5+ B cells to form CXCL13+CD4+ T cells:: CXCR5+ B cells:: CD8+ T cells triad, promoting the anti-tumor immunity and heralding a favorable prognosis. A CXCL13-expressing subset of CD4+ T cells was identified to be associated with better prognosis and tumor-reactive hallmarks. The further cell types interaction analysis revealed a specific interaction between CXCL13+CD4+ T cells and CXCR5+ B cells in comparison with other cell types. The mIHC verified that an elevated level of CXCR5+ B cells infiltration in the proximity of CXCL13+CD4+ T cells. The subsequent Entropy analysis, which characterizes the colocalization among more than two cell types, was employed to reveal the spatial distribution pattern. The results revealed that CXCL13+CD4+ T cells and CXCR5+ B cells co-localized with cytotoxic CD8+ T cells, forming a functional lymphocyte triad, whose existence heralded a better prognosis. Collectively, by integrating scRNA-seq with mIHC, we demonstrated that the recruitment of CXCR5+ B cells by neoantigen reacting to CXCL13+CD4+ T cells through CXCL13–CXCR5 signaling contributed to the lymphocyte triad, leading to an enhanced anti-tumor immunity and heralding a favorable prognosis in non-small-cell lung cancer (NSCLC).