4-1BB: A promising target for cancer immunotherapy - PMC Co-treatment of the 4-1BB antibody along with different classes of chemotherapy has been shown to elicit synergistic effects by preconditioning the immune environment, enhancing the proliferation of CD8 + cells following 4-1BB agonism, or by inducing 4-1BB expression (83–86)
New insights into the role of 4-1BB in immune responses . . . 4-1BB is expressed on activated CD4 + T cells, CD8 + T cells, natural killer (NK) cells and NK T cells (reviewed in [2]) CD4 + CD25 + regulatory T cells appear to express 4-1BB constitutively [3,4] Recent studies have shown that 4-1BB expression is not restricted to subpopulations of lymphoid cells but is distributed across a variety of cells
Expression and function of 4-1BB during CD4 versus CD8 T cell . . . 4-1BBL (- -) mice have a defect in recall CD8+ T cell responses to viruses, whereas CD4+ T cell responses to virus are unimpaired in these mice In contrast, both CD4+ and CD8+ T cells respond to 4-1BB ligand (4-1BBL) in vitro
Expression and function of 4-1BB during CD4 versus CD8 T cell . . . Although 4-1BB is expressed early in the primary response, there was no effect of 4-1BBL deficiency on initial CD8 T cell expansion and only a minor effect on initial CD4 T cell expansion The major effect of 4-1BB 4-1BBL interaction is on the T cell recall response
Role of 4-1BB Receptor in the Control Played by CD8+ T Cells . . . In vivo Ag85B stimulation induced 4-1BB expression on CD8 + T cells and in vivo 4-1BB ligation reduced the activation, IFN-γ production and expansion of Ag85B-specific CD4 + T cells of DNA-primed and protein-boosted mice