CD137 (4-1BB) ligand mediates CD4 T-cell immuno-surveillance of pre- lymphoma B cells in a lymphoma-prone mouse model

Aberrant expression of the proto-oncogene BCL6 is a driver of tumorigenesis in diffuse large B cell lymphoma (DLBCL). Mice overexpressing BCL6 from the B cell-specific immunoglobulin heavy chain µ intron promoter (Iµ-Bcl6 Tg/+ ) develop B cell lymphomas with features typical of human DLBCL. B cell lymphoma development in these mice is tightly controlled by T cells; however, the mechanisms of this immune surveillance are poorly understood. Here we show that CD4 T cells contribute to the control of lymphoproliferative disease in lymphoma-prone Iµ-Bcl6 Tg/+ mice. Furthermore, we reveal that this CD4 T-cell immuno-surveillance requires signaling by the co-stimulatory molecule, CD137 ligand (CD137L; also known as 4-1BBL), which promotes the transition of pre malignant B cells with an activated phenotype into the germinal center stage, preventing their hazardous accumulation. Thus, CD137L-mediated CD4 T cell immuno-surveillance adds another layer of protection against B-cell malignancy to that provided by CD8 T-cell cytotoxicity. Overall design: 12 samples for T cell sufficient lymphoma and 11 samples for T cell deficient lymphoma. Samples were ran in two runs and the sample T cell sufficient lymphoma_1/76_S1 was used as a reference sample between the two runs/batches. Sample 76_S1 from both batches are included in this series.