Tumor relapse prevented by combining adoptive T cell therapy with Salmonella typhimurium.

We recently reported that therapeutic vaccination with live tumor antigen-producing Salmonella typhimurium rescues dysfunctional endogenous T cell responses and eradicates long-established tumors refractory to αCTLA-4 and αPD-L1 checkpoint inhibitor blockade. Here, we show that live intravenously injected or heat-killed (HK) intratumorally injected Salmonella typhimurium, even when not producing tumor antigen, synergize with adoptive T cell therapy to eradicate tumors. These data demonstrate that the combination of adoptive T cell transfer with the injection of live or dead Salmonella typhimurium is a promising approach for cancer treatment.