Resumen:
The synergy mechanism can be traced to enhanced CTLA-4 expression in effector cells as a result of T(reg) elimination, thereby offering more targets to the blocking antibody. Human T cells and allogenic DCs (derived both from healthy donors and advanced cancer patients) were coinjected in the peritoneum of Rag2(-/-) IL-2R¿(-/-) mice. In these conditions, tremelimumab injected intravenously did not significantly enhance alloreactive proliferation unless T(reg) cells had been predepleted. Synergistic effects in vivo were again largely restricted to the CD4 T-cell compartment. In addition, T(reg) depletion and CTLA-4 blockade synergistically enhanced specific cytotoxicity raised in culture against autologous EBV-transformed cell lines. Taken together, these experiments indicate that tremelimumab therapy may benefit from previous or concomitant T(reg) depletion
