CD8 tumor-infiltrating lymphocytes (sorted 4-1BB+ CD25+ subset)

CD8 tumor-infiltrating lymphocytes (sorted 4-1BB+ CD25+ subset) is an autologous adoptive cell therapy being developed by the Earle A. Chiles Research Institute in collaboration with Agonox and Oregon Health and Science University. The therapy involves isolating CD8+ T cells from the tumor microenvironment, specifically targeting the CD39+ CD103+ double-positive population. Upon co-culture with autologous tumor cells, a highly reactive subset that upregulates 4-1BB (CD137) and CD25 (IL-2 receptor alpha) is sorted and expanded ex vivo. This specific subset has demonstrated superior tumor control and complete regression in xenograft models of melanoma brain metastasis compared to unsorted TIL populations, suggesting it contains the most potent tumor-reactive clones.