Background: Ly6C expression in naïve CD8+ T cells plays a crucial role in enhancing their effector activity, suggesting potential implications for cancer immunotherapy. This study investigates the functional impact of Ly6C expression on CD8+ T cells and explores albumin-conjugated IFNβ (Alb-IFNβ) as a strategy to modulate Ly6C expression and improve cancer vaccine efficacy. Methods: We analyzed the functional differences between Ly6C high-expressing (Ly6Chi) and Ly6C low-expressing (Ly6Clo) naïve CD8+ T cells in tumor suppression. To assess the role of type I interferon signaling, we administered Alb-IFNβ in C57BL/6J and IFNAR-/- mice and measured Ly6C expression in CD8+ T cells. The therapeutic potential of Alb-IFNβ was further evaluated in combination with a vaccinia virus encoding the HPV-16 E7 antigen (CRT-E7 vaccine) in a syngeneic TC-1 tumor model, assessing tumor growth, survival, and antigen-specific CD8+ T cell responses. Results: Naïve CD8+ T cells with elevated Ly6C expression exhibited enhanced tumor-suppressive capacity and required lower activation thresholds for effector function. Alb-IFNβ treatment selectively increased Ly6Chi naïve CD8+ T cells in C57BL/6J mice but not in IFNAR-/- mice, confirming type I interferon's role in Ly6C regulation. Combining Alb-IFNβ pretreatment with the CRT-E7 vaccine significantly enhanced antigen-specific CD8+ T cell immunity, reducing tumor growth and prolonging survival in TC-1 tumor-bearing mice. Conclusions: Our findings suggest that Alb-IFNβ may enhance the antitumor activity of naïve CD8+ T cells by modulating Ly6C expression. Alb-IFNβ could potentially improve the efficacy of HPV vaccinia-based cancer vaccines, warranting further investigation as an adjuvant strategy in cancer immunotherapy.

Pyroptosis, driven by the N-terminal domain of gasdermin proteins (GSDM), promotes antitumor immunity by attracting lymphocytes to the tumor microenvironment (TME). However, current pyroptosis-inducing therapies like drug injections and phototherapy are limited to localized treatments, making them unsuitable for widespread or microscopic metastatic lesions. This study engineered oncolytic M1 viruses (rM1-mGSDME_FL and rM1-mGSDME_NT) to selectively deliver GSDME to tumor cells. These modified viruses enhanced tumor cell death in breast cancer models, suppressed tumor growth, extended survival in mice, and boosted immune cell infiltration, demonstrating significant anticancer potential through pyroptosis induction.
© 2024 The Author(s).

Although the anti-PD-1+LAG-3 and the anti-PD-1+CTLA-4 combinations are effective in advanced melanoma, it remains unclear whether their mechanisms of action overlap.
We used single cell (sc) RNA-seq, flow cytometry and IHC analysis of responding SM1, D4M-UV2 and B16 melanoma flank tumors and SM1 brain metastases to explore the mechanism of action of the anti-PD-1+LAG-3 and the anti-PD-1+CTLA-4 combination. CD4+ and CD8+ T cell depletion, tetramer binding assays and ELISPOT assays were used to demonstrate the unique role of CD4+T cell help in the antitumor effects of the anti-PD-1+LAG-3 combination.
The anti-PD-1+CTLA-4 combination was associated with the infiltration of FOXP3+regulatory CD4+ cells (Tregs), fewer activated CD4+T cells and the accumulation of a subset of IFNγ secreting cytotoxic CD8+T cells, whereas the anti-PD-1+LAG-3 combination led to the accumulation of CD4+T helper cells that expressed CXCR4, TNFSF8, IL21R and a subset of CD8+T cells with reduced expression of cytotoxic markers. T cell depletion studies showed a requirement for CD4+T cells for the anti-PD-1+LAG-3 combination, but not the PD-1-CTLA-4 combination at both flank and brain tumor sites. In anti-PD-1+LAG-3 treated tumors, CD4+T cell depletion was associated with fewer activated (CD69+) CD8+T cells and impaired IFNγ release but, conversely, increased numbers of activated CD8+T cells and IFNγ release in anti-PD-1+CTLA-4 treated tumors.
Together these studies suggest that these two clinically relevant immune checkpoint inhibitor (ICI) combinations have differential effects on CD4+T cell polarization, which in turn, impacted cytotoxic CD8+T cell function. Further insights into the mechanisms of action/resistance of these clinically-relevant ICI combinations will allow therapy to be further personalized.
© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

The current paradigm indicates that naive T cells are primed in secondary lymphoid organs. Here, we present evidence that intranasal administration of peptide antigens appended to nanofibers primes naive CD8+ T cells in the lung independently and prior to priming in the draining mediastinal lymph node (MLN). Notably, comparable accumulation and transcriptomic responses of CD8+ T cells in lung and MLN are observed in both Batf3KO and wild-type (WT) mice, indicating that, while cDC1 dendritic cells (DCs) are the major subset for cross-presentation, cDC2 DCs alone are capable of cross-priming CD8+ T cells both in the lung and draining MLN. Transcription analyses reveal distinct transcriptional responses in lung cDC1 and cDC2 to intranasal nanofiber immunization. However, both DC subsets acquire shared transcriptional responses upon migration into the lymph node, thus uncovering a stepwise activation process of cDC1 and cDC2 toward their ability to cross-prime effector and functional memory CD8+ T cell responses.
Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.

Background Although the anti-PD-1+LAG-3 and the anti-PD-1+CTLA-4 combinations are effective in advanced melanoma it remains unclear whether their mechanisms of action and resistance overlap. Methods We used single cell (sc) RNA-seq, flow cytometry and IHC analysis of responding SM1 and B16 melanoma flank tumors and SM1 brain metastases to explore the mechanism of action of the anti-PD-1+LAG-3 and the anti-PD-1+CTLA-4 combination. CD4+ and CD8+ T cell depletion and ELISPOT assays were used to demonstrate the unique role of CD4+ T cell help in the anti-tumor effects of the anti-PD-1+LAG-3 combination. Tetramer assays confirmed the loss of CD8+ tumor-reactive T cells in brain tumors resistant to the anti-PD-1+LAG-3 combination. Results The anti-PD-1+CTLA-4 combination was associated with the infiltration of FOXP3+ regulatory CD4+ cells (Tregs), fewer activated CD4+ T cells and the accumulation of a subset of IFNγ secreting cytotoxic CD8+ T cells, whereas the anti-PD-1+LAG-3 combination led to the accumulation of CD4+ T helper cells that expressed CXCR4, TNFSF8, IL21R and a subset of CD8+ T cells with reduced expression of cytotoxic markers. T cell depletion studies showed a requirement for CD4+ T cells for the anti-PD-1+LAG-3 combination, but not the PD-1-CTLA-4 combination at both flank and brain tumor sites. In anti-PD-1+LAG-3 treated tumors, CD4+ T cell depletion was associated with fewer activated (CD69+) CD8+ T cells, impaired IFNγ release and increased numbers of myeloid-derived suppressor cells (MDSCs) but, conversely, increased numbers of activated CD8+ T cells and IFNγ release in anti-PD-1+CTLA-4 treated tumors. Analysis of relapsing melanoma brain metastases from anti-PD-1+LAG-3 treated mice showed an increased accumulation of MDSCs and a loss of gp100+ tumor reactive CD8+ T cells. An analysis of the inferred cell-cell interactions from the scRNA-seq data suggested the MDSCs interacted with multiple subsets of T cells in a bi-directional manner. Conclusions Together these studies suggest that these two clinically relevant ICI combinations have differential effects upon CD4+ T cell polarization, which in turn, impacted cytotoxic CD8+ T cell function. Further insights into the mechanisms of action/resistance of these clinically-relevant ICI combinations will allow therapy to be further personalized.