Moustaki et al. showed that in young (as compared to adult) tumor-bearing (TB) mice, CD8+ T effector cells in peripheral lymphoid organs were hyperactivated, and in tumors, were fully differentiated/functionally exhausted; migratory DCs in dLNs were more activated and matured. “Young” dLN DCs and pro-inflammatory M1-like mononuclear phagocytes more effectively captured and cross-presented tumor antigen to CD8+ T cells. Analysis of 83 pediatric specimens comprising 34 different solid tumor types showed that enrichment of exhausted CD8+PD-1hiTIM3hi T cells correlated with presence of more PD-L1+ myeloid cells.
Contributed by Paula Hochman
ABSTRACT: The immune system undergoes a progressive functional remodeling with age. Understanding how age bias shapes antitumor immunity is essential in designing effective immunotherapies, especially for pediatric patients. Here, we explore antitumor CD8(+) T cell responses generated in young (prepubescent) and adult (presenescent) mice. Using an MHCI-deficient tumor model, we observed that tumor-reactive CD8(+) T cells expanded in young tumor-bearing (TB) mice acquired a terminally differentiated phenotype characterized by overexpression of inhibitory receptors and the transcription factor Tox1. Furthermore, tumor-infiltrating CD8(+) T cells from young tumors yielded a poor cytokine response compared with CD8(+) T cells infiltrating adult tumors. Young migratory dendritic cells (migDCs) from the draining lymph nodes (dLNs), and mononuclear phagocytic cells (MPCs) infiltrating young tumors, were more competent in capturing and cross-presenting tumor antigen, leading to enhanced priming of CD8(+) T cells in dLNs and their subsequent terminal differentiation in the tumors. Single-cell transcriptional profiling of tumor-infiltrating MPCs demonstrated that young MPCs are polarized toward an inflammatory, effector phenotype. Consistent with our observations in young versus adult TB mice, analysis of immune infiltrates from pediatric solid tumors showed a correlation between tumor-infiltrating CD8(+) T cells with an exhaustion phenotype and the frequency of PD-L1-expressing monocytes/macrophages. Collectively, these data indicate that a young tissue microenvironment contributes to the generation of an immune response skewed toward a less pliable terminal effector state, thus narrowing the window for immunotherapeutic interventions.
Author Info: (1) Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (2) Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105,
Author Info: (1) Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (2) Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (3) Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (4) Center for Applied Bioinformatics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (5) Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (6) Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (7) Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. University of Tennessee Health and Science Center (UTHSC), Memphis, TN 38163. (8) Center for Applied Bioinformatics, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (9) Department of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (10) Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (11) Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (12) Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (13) Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (14) Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (15) Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN 38105, USA. (16) Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (17) Department of Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA. (18) Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
