biostudies-literatureO'Melia MJSusan G. KomenFoundation for the National Institutes of HealthNCI NIH HHSNIH HHSNIGMS NIH HHS2179-2195https://www.ebi.ac.uk/biostudies/studies/S-EPMC8286278biostudies-literatureUnknown70(8)Triple negative breast cancer (TNBC) is a significant clinical problem to which immunotherapeutic strategies have been applied with limited success. Using the syngeneic E0771 TNBC mouse model, this work explores the potential for antitumor CD8⁺ T cell immunity to be primed extratumorally in lymphoid tissues and therapeutically leveraged. CD8⁺ T cell viability and responses within the tumor microenvironment (TME) were found to be severely impaired, effects coincident with local immunosuppression that is recapitulated in lymphoid tissues in late stage disease. Prior to onset of a locally suppressed immune microenvironment, however, CD8⁺ T cell priming within lymph nodes (LN) that depended on tumor lymphatic drainage remained intact. These results demonstrate Cancer immunology, immunotherapy : CIITumor-draining lymph nodes are survival niches that support T cell priming against lymphatic transported tumor antigen and effects of immune checkpoint blockade in TNBC.PMC8286278S10OD016264T32GM008433R01CA207619S10 OD016264CCR15330478T32 GM008433R01 CA207619U01 CA214354U01CA214354Manspeaker MPThomas SNO'Melia MJfalseTumor-draining lymph nodes are survival niches that support T cell priming against lymphatic transported tumor antigen and effects of immune checkpoint blockade in TNBC.Triple negative breast cancer (TNBC) is a significant clinical problem to which immunotherapeutic strategies have been applied with limited success. Using the syngeneic E0771 TNBC mouse model, this work explores the potential for antitumor CD8⁺ T cell immunity to be primed extratumorally in lymphoid tissues and therapeutically leveraged. CD8⁺ T cell viability and responses within the tumor microenvironment (TME) were found to be severely impaired, effects coincident with local immunosuppression that is recapitulated in lymphoid tissues in late stage disease. Prior to onset of a locally suppressed immune microenvironment, however, CD8⁺ T cell priming within lymph nodes (LN) that depended on tumor lymphatic drainage remained intact. These results demonstrate 2021-01-01T00:00:00Z2021 Aug2025-04-04T01:23:55.523Z2025-04-04T01:23:55.523ZS-EPMC82862783345984210.1007/s00262-020-02792-5