Negative co-stimulatory signaling mediated via cell surface programmed death (PD)-1 expression modulates T and B cell activation and is involved in maintaining peripheral tolerance. In this study, we examined the effects of a fully human PD-1-abrogating antibody on the in vitro expansion and function of human vaccine-induced CD8+ T cells (CTLs) specific for the melanoma-associated antigens glycoprotein 100 (gp100) and melanoma antigen recognized by T cells (MART)-1. PD-1 blockade during peptide stimulation augmented the absolute numbers of CD3+, CD4+, CD8+ and gp100/MART-1 MHC:peptide tetramer+ CTLs. This correlated with increased frequencies of IFN-gamma-secreting antigen-specific cells and augmented lysis of gp100+/MART-1+ melanoma targets. PD-1 blockade also increased the fraction of antigen-specific CTLs that recognized melanoma targets by degranulation, suggesting increased recognition efficiency for cognate peptide. The increased frequencies and absolute numbers of antigen-specific CTLs by PD-1 blockade resulted from augmented proliferation, not decreased apoptosis. Kinetic analysis of cytokine secretion demonstrated that PD-1 blockade increased both type-1 and type-2 cytokine accumulation in culture without any apparent skewing of the cytokine repertoire. These findings have implications for developing new cancer immunotherapy strategies.
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http://dx.doi.org/10.1093/intimm/dxm091 | DOI Listing |
Front Immunol
December 2024
Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea.
Introduction: T-lymphopenia (TLP) is a frequently observed condition in cancer patients, often exacerbated by conventional chemo/radiotherapy, which impairs the efficacy of subsequent immune checkpoint blockade (ICB) therapy. This study aimed to understand the impact of TLP on ICB responsiveness and explore potential therapeutic strategies to enhance antitumor immunity.
Methods: To investigate ICB responsiveness depending on the severity of TLP, first, we established TLP mouse models that mimic clinically observed mild and severe TLP through thymectomy and anti-Thy1-induced peripheral T cell depletion.
Nat Med
January 2025
Department of General Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
Radiotherapy displays unique antitumor synergism with immune checkpoint inhibitors, which is indicated by high pathological complete response (pCR) rates from single-arm trials of locally advanced rectal cancer (LARC). Here we test the efficacy and safety of the radiation-immune checkpoint inhibitor combination in patients with LARC in a phase 2, randomized trial conducted in eight major colorectal cancer centers in Beijing. In total, 186 eligible all-comer (proficient mismatch repair and deficient mismatch repair) participants were enrolled.
View Article and Find Full Text PDFSci Rep
January 2025
Thoracic and GI Malignancies Branch, National Institutes of Health, 10 Center Drive, 2B50C, Bethesda, MD, 20892, USA.
Human papillomavirus (HPV)-negative head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer type in the world and is associated with an overall poor prognosis. The protein methyltransferase SET and MYND domain-containing 3 (SMYD3), which trimethylates H3K4, activates gene transcription and enhances several oncogenic pathways, including epithelial-mesenchymal transition and cell cycle related pathways, in various cancer types. It was also recently shown that SMYD3 is overexpressed in HPV-negative HNSCC, and represses the expression of type I IFN response genes, contributing to resistance to anti-PD-1 checkpoint blockade in this disease.
View Article and Find Full Text PDFJ Immunother Cancer
January 2025
State Key Laboratory of Systems Medicine for Cancer of Oncology Department and Shanghai Cancer Institute, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
Background: To date, a growing body of evidence suggests that unfolded protein response (UPR) sensors play a vital role in carcinogenesis. However, it remains unclear whether they are involved in pancreatic ductal adenocarcinoma (PDAC) and how they relate to clinical outcomes. This study aims to investigate the biological function and mechanism of how a novel UPR sensor, CREB3L1 works in PDAC and further evaluate its clinical application prospect.
View Article and Find Full Text PDFJ Immunother Cancer
January 2025
Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
Background: Immune checkpoint inhibitors targeting programmed cell death protein-1 (PD-1) are the first line of treatment for many solid tumors including melanoma. PD-1 blockade enhances the effector functions of melanoma-infiltrating CD8 T cells, leading to durable tumor remissions. However, 55% of patients with melanoma do not respond to treatment.
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