Bidirectional regulation of the gut microbiome-immune axis in the immune microenvironment of colorectal cancer and targeted interventions

Figure 2 Mechanism of antigen presentation-induced cluster of differentiation 8+ T cell-specific immune response. The mechanism involves five steps: (1) Tumor antigen release: Tumor cells shed or release antigens; (2) Antigen presentation by dendritic cells (DC): DC, a type of antigen-presenting cells (APCs), capture and process these tumor antigens; (3) Activation of cluster of differentiation (CD)8+ T cells by APCs: The APCs then activate CD8+ T cells through antigen presentation; (4) Migration of activated CD8+ T cells to the tumor site: Activated CD8+ T cells migrate toward the tumor location; and (5) CD8+ T cell-mediated tumor cell killing: Finally, CD8+ T cells exert cytotoxic effects and eliminate tumor cells. APCs: Antigen-presenting cells; DC: Dendritic cells; CD: Cluster of differentiation.