Fig. 1

Interactions between PDAC cells and lymphocytes in TIME. Tumor cells inhibit the normal function of CD8⁺ effector T cells by upregulating the expression of multiple checkpoint ligands. Tumor cells also inhibited the activation of NK cells, CD4⁺ T cells, and B cells. By releasing a variety of immunosuppressive factors, tumor cells promote the activation of Tregs and Bregs. All these make the microenvironment present a state of immune exhaustion. Red arrows represent tumor-promoting processes. Pink circles represent possible treatment strategies. TIGIT: T cell immunoreceptor with Ig and ITIM domains; C-FOXP3: cancer Forkhead box protein 3; APC: antigen presenting cell; BTK: Bruton's tyrosine kinase; Breg: regulatory B cell