PDCD1 and neoplasm: These two bacteria induce the production of IL-12, a Th1-type cytokine, in dendritic cells, stimulating the production of intestinal CD4+ T cells that express CCR9 receptors for chymosins in tumour beds, lymph nodes that drain the tumour, and in the mesenteric lymph nodes, exerting an adjuvant effect on the anti-PD-1 response.