T-cell infiltration

T-cell infiltration is the biological process by which T-lymphocytes migrate from the bloodstream into a specific tissue or the tumor microenvironment (TME). This process is mediated by a complex signaling cascade involving selectins, integrins, and chemokines like CXCL9 and CXCL10, which facilitate T-cell adhesion and transendothelial migration (PubMed: 28231530). In oncology, the presence and density of infiltrating CD8+ cytotoxic T-cells are critical markers of 'immunologically hot' tumors and are strongly associated with better clinical outcomes and responsiveness to immunotherapy (NIH: PMC5824106). Conversely, in autoimmune and inflammatory diseases, the infiltration of T-cells into healthy tissues causes chronic damage and organ dysfunction. While T-cell infiltration is a phenotypic outcome rather than a single protein or receptor, it is a primary therapeutic objective for many immuno-oncology agents. These drugs, such as immune checkpoint inhibitors, work by overcoming immunosuppressive barriers to allow successful T-cell entry and activity within the tumor (Nature Reviews Cancer: 10.1038/nrc.2016.18). Consequently, measuring infiltration through methods like the Immunoscore serves as a vital diagnostic tool for patient stratification.

Other names

Tumor-infiltrating lymphocytes recruitmentT-cell migrationT-cell homingLymphocyte extravasationTIL infiltration

Enhancement or modulation of lymphocyte recruitment, extravasation, and retention within tissues via checkpoint inhibition or cytokine/chemokine signaling.