We have previously shown that immune checkpoint receptors, including PD-1, are upregulated on T cells at the time of their activation, and that blockade of these receptors can improve the efficacy of antitumor vaccines. In the present study, we sought to determine whether, and by what mechanisms, the timing of PD-1 blockade with respect to vaccination affects antitumor T cell function.
TRAMP-C1 or E.G7-OVA tumor-bearing mice received PD-1 blockade at different timing intervals with a tumor-associated antigen vaccine. Tumor growth, survival, and immune-infiltrating populations were assessed. In vitro models of T cell activation using OT-I T cells and PD-(L)1 axis disruption with a PD-1 blocking antibody or PD-L1KO dendritic cells were used.
Mice receiving PD-1 blockade at the time of T cell activation with vaccine had better antitumor outcomes in comparison to mice receiving PD-1 blockade before or after immunization. T cells activated in vitro in the presence of PD-(L)1 axis disruption had a more differentiated, functional phenotype with decreased CD28 and CCR7 expression and increased production of the Tc1 cytokines IL-2, TNFα, and IFNγ. Intriguingly, a small subset of undifferentiated cells (CD28+) was of a stem-like Tc17 phenotype (IL-17α+, TCF1+). Tumor-bearing mice receiving T cells activated in the presence of PD-(L)1-axis disruption had better antitumor outcomes and a greater number of complete responses.
These data indicate that PD-1 blockade, when used with antitumor vaccines, acts primarily at the time of T cell activation, not exclusively within the tumor microenvironment. Consequently, PD-1 blockade may be best used when delivered concurrently with T cell activating agents such as vaccines.
© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.

Background: Alzheimer's Disease (AD) is a neuropathological condition marked by cognitive deterioration and chronic neuroinflammation. Previous investigations have unveiled a strong correlation between the gut microbiota and the progression of AD. In this study, our objective is to probe the effects of Parabacteroides distasonis ( P.distasonis ), previously found to be conspicuously diminished in AD patients, on the APP/PS1 mice model. Methods: : To assess the impact of orally administered P.distasonis on gut microbiota and metabolites, we utilized 16s rDNA sequencing and GC-MS to analyze gut composition and short-chain fatty acids in APP/PS1 mice after one month of P.distasonis gavage. To investigate the effects of P.distasonis administration over a six-month period on APP/PS1 mice, we evaluated cognitive function using novel object recognition and Y-maze tests, assessed intestinal barrier integrity and AD-related pathological features with immunofluorescence, and analyzed immune cell subpopulations in intestine, blood, spleen, and brain tissues via flow cytometry. The Luminex assay was employed to detect inflammatory cytokine secretion in the same regions. Results: : One-month oral administration of P.distasonis modulated the gut microbiota, elevated butyrate levels. Six-month oral administration of P.distasonis improved cognitive function in APP/PS1 mice, reducing Aβ deposition and inhibiting glial cell proliferation. It also amplified Treg cells within the gut, concomitant with the decreased Th1 proliferation and intestinal inflammation. Additionally, we observed the migration of peripheral CD4 + T cells to the brain through chemotaxis, accompanied by an increase in Treg cells and higher levels of anti-inflammatory factors such as IL-10 and TGF-β in the brain. Collectively, these multifaceted effects contributed to the alleviation of neuroinflammation. Conclusion: These findings underscore the potential of transplanting P.distasonis in alleviating AD-related pathology, suggesting a role for gut microbiota in neuroinflammation attenuation.

Lymph nodes (LNs) are critical sites for shaping tissue-specific adaptive immunity. However, the impact of LN sharing between multiple organs on such tailoring is less understood. Here, we describe the drainage hierarchy of the pancreas, liver, and the upper small intestine (duodenum) into three murine LNs. Migratory dendritic cells (migDCs), key in instructing adaptive immune outcome, exhibited stronger pro-inflammatory signatures when originating from the pancreas or liver than from the duodenum. Qualitatively different migDC mixing in each shared LN influenced pancreatic β-cell-reactive T cells to acquire gut-homing and tolerogenic phenotypes proportional to duodenal co-drainage. However, duodenal viral infections rendered non-intestinal migDCs and β-cell-reactive T cells more pro-inflammatory in all shared LNs, resulting in elevated pancreatic islet lymphocyte infiltration. Our study uncovers immune crosstalk through LN co-drainage as a powerful force regulating pancreatic autoimmunity.
Copyright © 2023 Elsevier Inc. All rights reserved.

Neoantigen vaccines constitute an emerging and promising cancer immunotherapy. However, not all neoantigens have anti-tumor activity, as poor CD4+ epitope recognition can lead to the lack of greatly limit the persistence of the CD8+ T cell response. Therefore, we designed a self-assembled nanoplatform hereinafter referred to as DNA-coupled nitrated T helper cell epitope nanoparticle (DCNP) based on DNA origami containing a nitrated CD4 + T cell epitope, which can facilitate the effective activation of neoantigen-specific CD8+  T cells. Moreover, we embedded the cytidine-phosphate-guanosine oligonucleotide (CpG ODN) motif sequence in the DNA skeleton to function as a built-in adjuvant to activate Toll-like receptor 9. DCNP can markedly improve adjuvant and neoantigen co-delivery to lymphoid organs and promote neoantigen presentation on dendritic cells. Moreover, DCNP induced robust, and long-lived neoantigen-specific CD8+ T cell responses that significantly delayed tumor growth. Further, these effects were largely dependent on the nitrated T cell epitope. Collectively, our findings indicate that DCNP is a promising platform that could improve the development of personalized therapeutic neoantigen vaccines for cancer immunotherapy.
© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Reprogramming of immunosuppressive tumor-associated macrophages (TAMs) presents an attractive therapeutic strategy in cancer. The aim of this study was to explore the role of macrophage CD5L protein in TAM activity and assess its potential as a therapeutic target.
Monoclonal antibodies (mAbs) against recombinant CD5L were raised by subcutaneous immunization of BALB/c mice. Peripheral blood monocytes were isolated from healthy donors and stimulated with IFN/LPS, IL4, IL10, and conditioned medium (CM) from different cancer cell lines in the presence of anti-CD5L mAb or controls. Subsequently, phenotypic markers, including CD5L, were quantified by flow cytometry, IF and RT-qPCR. Macrophage CD5L protein expression was studied in 55 human papillary lung adenocarcinoma (PAC) samples by IHC and IF. Anti-CD5L mAb and isotype control were administered intraperitoneally into a syngeneic Lewis Lung Carcinoma mouse model and tumor growth was measured. Tumor microenvironment (TME) changes were determined by flow cytometry, IHC, IF, Luminex, RNAseq and RT-qPCR.
Cancer cell lines CM induced an immunosuppressive phenotype (increase in CD163, CD206, MERTK, VEGF and CD5L) in cultured macrophages. Accordingly, high TAM expression of CD5L in PAC was associated with poor patient outcome (Log-rank (Mantel-Cox) test p = 0.02). We raised a new anti-CD5L mAb that blocked the immunosuppressive phenotype of macrophages in vitro. Its administration in vivo inhibited tumor progression of lung cancer by altering the intratumoral myeloid cell population profile and CD4+ T-cell exhaustion phenotype, thereby significantly modifying the TME and increasing the inflammatory milieu.
CD5L protein plays a key function in modulating the activity of macrophages and their interactions within the TME, which supports its role as a therapeutic target in cancer immunotherapy.
For a full list of funding bodies, please see the Acknowledgements.
Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.