Shapiro, D. D.; Nichols, K. D.; Lee, M. H.; Msaouel, P.; Li, Y.; Zong, Y.; Hu, R.; Huang, W.; Esbona, K.; Kinoshita, T.; Lotan, P.; Roadman, D. F.; Nkadori, E.; McGregor, S. M.; Beebe, D. J.; Kerr, S. C.; Capitini, C. M.; Abel, E. J.

Clear cell renal cell carcinoma (ccRCC) exhibits heterogeneity in immune infiltration and clinical outcomes, but the mechanisms governing recruitment and organization of tumor-reactive CD8+ T cells remain incompletely defined. We investigated the role of the CXCL13-CXCR5 axis in shaping CD8+ T cell recruitment, differentiation, and immune organization in high-risk, non-metastatic ccRCC. Human tumor, plasma, and matched adjacent kidney specimens were analyzed using ELISA, quantitative PCR, migration assays, multiplex immunofluorescence, single-cell RNA sequencing, spatial transcriptomics, and a syngeneic mouse model. CXCL13 was among the most upregulated chemokines in ccRCC relative to matched normal kidney and was embedded within a CD8+T cell-associated inflammatory transcriptional program. In transwell and microphysiological system (MPS) assays, CXCL13 promoted CD8+ T cell migration, enriched CXCR5+ cells among migrating CD8+ T cells and showed reduced migration after CXCL13 or CXCR5 blockade. Single-cell analyses identified CXCR5 expression within stem-like CD8+ T cell states associated with TCF7 and IL7R, whereas CXCL13 associated with later cytotoxic/exhausted states along a continuous differentiation landscape. Spatial transcriptomics demonstrated that stem-like CD8+ T cells localized within structured lymphoid aggregates enriched for B cells, coordinated CXCL13/CXCR5 expression, and signaling programs. In vivo, tumor-derived CXCL13 suppressed tumor growth, increased intratumoral CD8+ T cell infiltration, and enriched CXCR5+TCF1+CD8+ stem-like T cells. In human tumors, higher CXCL13 expression correlated with increased CXCR5+CD8+ T cell infiltration and improved recurrence-free survival. These findings identify CXCL13 as a regulator of immune recruitment and niche organization and support the CXCL13-CXCR5 axis as a biomarker and possible therapeutic target in ccRCC.