CD4 and neoplasm: They reported a preferential accumulation of transformed Salmonella in tumor tissues [143] and found that the intratumoral injection of siRNA-PD-1-carrying Salmonella resulted in (a) a remarkable decrease in tumor weight, (b) prolonged survival rate of tumor bearing mice, in addition to (c) an increase in CD4+ and CD8+ TILs compared to treatment with Salmonella containing a plasmid for scrambled si-RNA [143,144].