Non-healing venous leg ulcers are characterized by dysfunctional wound healing and frequently exhibit an absence of classical inflammatory signs, despite substantial bacterial loads of the Gram-negative pathogen Pseudomonas aeruginosa. To investigate this clinical observation, we used a porcine wound infection model and complementary in vitro cell and enzymatic activity assays. In vivo, P. aeruginosa infected wounds resulted in attenuated inflammatory responses compared to those infected with Staphylococcus aureus. Protease activity was elevated in P. aeruginosa-infected wounds relative to uninfected controls, while pro-inflammatory cytokine levels decreased over time. In vitro analyses employing cell cultures, wildtype and mutant strains, and clinical isolates from venous ulcers and blood, revealed that P. aeruginosa elastase (LasB) degrades a range of pro-inflammatory cytokines (G-CSF, GM-CSF, IFN-γ, IL-1ra, IL-6, IL-12p40, IL-23, TNF-α) and chemokines (Gro-α, IL-8, IP-10, MCP-1, MIP-1α, MIP-1β) in the extracellular milieu, without impacting cell morphology, transcription factor activation, or subsequent intracellular cytokine production. Correspondingly, wound fluids from non-healing ulcers colonized/infected with P. aeruginosa degraded cytokines, whereas fluids from uninfected wounds did not. Collectively, our findings indicate that P. aeruginosa modulates host inflammation by degrading cytokines and chemokines.
Copyright © 2025 van der Plas, Puthia, Ong, Arkelius, Strömdahl, Butrym, Rasmussen, Verma and Schmidtchen.

The systematic immune status of cancer patients undergoing immunotherapy is little known. We prospectively identified the function and differentiation traits of peripheral CD8+ T cells based on our phase 1b clinical trial (NCT03222440) of radiotherapy combined with camrelizumab in patients with locally advanced esophageal squamous cell carcinoma (ESCC) and compared it with concurrent chemoradiotherapy (CCRT).
19 and 18 patients were included in the cohort of radiotherapy plus camrelizumab and cohort of CCRT treatment. By using flow cytometry, we evaluated the expression levels of PD-1, Eomes, T-bet and IFN-γ (function), CD38 and HLA-DR (activation), and differentiation subsets classified according to the expression levels of CD45RA and CD62L in peripheral CD8+ T cells before and during treatment.
Effective binding of anti-PD-1 antibody camrelizumab with PD-1 on CD8+ T cells was detected during treatment. Both two treatments elevated the expression levels of activation molecules CD38 and HLA-DR on CD8+ T cells. PD-1+CD8+ T cells had more activation features than PD-1-CD8+ T cells in two groups and the treatments did not alter these differences. The two treatments activated both PD-1+ and PD-1- CD8+ T cells. PD-1+CD8+ T cells had less Naïve and TEMRA but more Tcm and Tem than PD-1-CD8+ T cells in two groups and both two treatments changed the ratio of memory T cells in PD-1+ and PD-1- cells. RT plus camrelizumab treatment reduced Naïve T cells and TEMRA subsets both in PD-1+ and PD-1- CD8+ T cells while elevated Tcm subset in PD-1+CD8+ T cells and Tem subset in PD-1-CD8+ T cells. CCRT elevated Tcm subset and reduced TEMRA subset in PD-1-CD8+ T cells while did not change any subset in PD-1+CD8+ T cells. Furthermore, patients undergoing radiotherapy plus immunotherapy were found to obtain better prognosis than those receiving CCRT.
This study identified the dynamic changes of systematic immune status of patients undergoing treatment. The two treatments had similar activation effects on peripheral CD8+ T cells with different PD-1 properties but had different effects on their differentiation status. These results provided potential clues to the reasons underlying the difference in prognosis of the two treatments.
Copyright © 2022 Wei, Li, Guo, Ma, Li, Wei, Han, Zhang, Chen, Yan, Zhou, Pang, Wang and Zhang.

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by beta-coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has rapidly spread across the globe starting from February 2020. It is well established that during viral infection, extracellular vesicles become delivery/presenting vectors of viral material. However, studies regarding extracellular vesicle function in COVID-19 pathology are still scanty. Here, we performed a comparative study on exosomes recovered from the plasma of either MILD or SEVERE COVID-19 patients. We show that although both types of vesicles efficiently display SARS-CoV-2 spike-derived peptides and carry immunomodulatory molecules, only those of MILD patients are capable of efficiently regulating antigen-specific CD4+ T-cell responses. Accordingly, by mass spectrometry, we show that the proteome of exosomes of MILD patients correlates with a proper functioning of the immune system, while that of SEVERE patients is associated with increased and chronic inflammation. Overall, we show that exosomes recovered from the plasma of COVID-19 patients possess SARS-CoV-2-derived protein material, have an active role in enhancing the immune response, and possess a cargo that reflects the pathological state of patients in the acute phase of the disease.
Copyright © 2022 Pesce, Manfrini, Cordiglieri, Santi, Bandera, Gobbini, Gruarin, Favalli, Bombaci, Cuomo, Collino, Cricrì, Ungaro, Lombardi, Mangioni, Muscatello, Aliberti, Blasi, Gori, Abrignani, De Francesco, Biffo and Grifantini.

The complement system is activated in tuberculous pleural effusion (TPE), with increased levels of the anaphylatoxins stimulating pleural mesothelial cells (PMCs) to secrete chemokines, which recruit nonclassical monocytes to the pleural cavity. The differentiation and recruitment of naive CD4+ T cells are induced by pleural cytokines and PMC-produced chemokines in TPE. However, it is unclear whether anaphylatoxins orchestrate CD4+ T cell response via interactions between PMCs and monocytes in TPE. In this study, CD16+ and CD16- monocytes isolated from TPE patients were cocultured with PMCs pretreated with anaphylatoxins. After removing the PMCs, the conditioned monocytes were cocultured with CD4+ T cells. The levels of the cytokines were measured in PMCs and monocyte subsets treated separately with anaphylatoxins. The costimulatory molecules were assessed in conditioned monocyte subsets. Furthermore, CD4+ T cell response was evaluated in different coculture systems. The results indicated that anaphylatoxins induced PMCs and CD16+ monocytes to secrete abundant cytokines capable of only inducing Th17 expansion, but Th1 was feeble. In addition, costimulatory molecules were more highly expressed in CD16+ than in CD16- monocytes isolated from TPE. The interactions between monocytes and PMCs enhanced the ability of PMCs and monocytes to produce cytokines and that of monocytes to express HLA-DR, CD40, CD80 and CD86, which synergistically induced Th17 expansion. In the above process, anaphylatoxins enhanced the interactions between monocytes and PMCs by increasing the level of the cytokines IL-1β, IL-6, IL-23 and upregulating the phenotype of CD40 and CD80 in CD16+ monocytes. Collectively, these data indicate that anaphylatoxins play a central role in orchestrating Th17 response mainly via interactions between CD16+ monocytes and PMCs in TPE.

An ability to activate latent HIV-1 expression could benefit many HIV cure strategies, but the first generation of latency reversing agents (LRAs) has proven disappointing. We evaluated AKT/mTOR activators as a potential new class of LRAs. Two glycogen synthase kinase-3 inhibitors (GSK-3i's), SB-216763 and tideglusib (the latter already in phase II clinical trials) that activate AKT/mTOR signaling were tested. These GSK-3i's reactivated latent HIV-1 present in blood samples from aviremic individuals on antiretroviral therapy (ART) in the absence of T cell activation, release of inflammatory cytokines, cell toxicity, or impaired effector function of cytotoxic T lymphocytes or NK cells. However, when administered in vivo to SIV-infected rhesus macaques on suppressive ART, tideglusib exhibited poor pharmacodynamic properties and resulted in no clear evidence of significant SIV latency reversal. Whether alternative pharmacological formulations or combinations of this drug with other classes of LRAs will lead to an effective in vivo latency-reversing strategy remains to be determined.IMPORTANCE If combined with immune therapeutics, latency reversing agents (LRAs) have the potential to reduce the size of the reservoir sufficiently that an engineered immune response can control the virus in the absence of antiretroviral therapy. We have identified a new class of LRAs that do not induce T-cell activation and that are able to potentiate, rather than inhibit, CD8+ T and NK cell cytotoxic effector functions. This new class of LRAs corresponds to inhibitors of glycogen synthase kinase-3. In this work, we have also studied the effects of one member of this drug class, tideglusib, in SIV-infected rhesus monkeys. When tested in vivo, however, tideglusib showed unfavorable pharmacokinetic properties, which resulted in lack of SIV latency reversal. The disconnect between our ex vivo and in vivo results highlights the importance of developing next generation LRAs with pharmacological properties that allow systemic drug delivery in relevant anatomical compartments harboring latent reservoirs.
Copyright © 2021 American Society for Microbiology.