We previously developed an innovative strategy to induce CD8+ T lymphocyte-immunity through in vivo engineering of extracellular vesicles (EVs). This approach relies on intramuscular injection of DNA expressing antigens of interest fused at a biologically-inactive HIV-1 Nef protein mutant (Nefmut). Nefmut is very efficiently incorporated into EVs, thus conveying large amounts of fusion proteins into EVs released by transfected cells. This platform proved successful against highly immunogenic tumor-specific antigens. Here, we tested whether antigen-specific CD8+ T cell immune responses induced by engineered EVs can counteract the growth of tumors expressing two "self" tumor-associated antigens (TAAs): HOXB7 and Her2/neu. FVB/N mice were injected with DNA vectors expressing Nefmut fused to HOXB7 or Her2/neu, singly and in combination, before subcutaneous implantation of breast carcinoma cells co-expressing HOXB7 and Her2/neu. All mice immunized with the combination vaccine remained tumor-free, whereas groups vaccinated with single Nefmut-fused antigens were only partly protected, with stronger antitumor effects in Her2/neu-immunized mice. Double-vaccinated mice also controlled tumor growth upon a later tumor cell re-challenge. Importantly, co-vaccination also contained tumors in a therapeutic immunization setting. These results showed the efficacy of EV-based vaccination against two TAAs, and represent the first demonstration that HOXB7 may be targeted in multi-antigen immunotherapy strategies.
© 2024. The Author(s).

Inflammatory bowel disease alters the gut microbiota, causes defects in mucosal barrier function, and leads to dysregulation of the immune response to microbial stimulation. This study investigated and compared the efficacy of a candidate probiotic strain, Bacillus coagulans BC198, and its heat-killed form in treating dextran sulfate sodium-induced colitis. Both live and heat-killed B. coagulans BC198 increased gut barrier-associated protein expression, reduced neutrophil and M1 macrophage infiltration of colon tissue, and corrected gut microbial dysbiosis induced by colitis. However, only live B. coagulans BC198 could alleviate the general symptoms of colitis, prevent colon shortening, and suppress inflammation and tissue damage. At the molecular level, live B. coagulans BC198 was able to inhibit Th17 cells while promoting Treg cells in mice with colitis, reduce pro-inflammatory MCP-1 production, and increase anti-inflammatory IL-10 expression in the colonic mucosa. The live form of B. coagulans BC198 functioned more effectively than the heat-killed form in ameliorating colitis by enhancing the anti-inflammatory response and promoting Treg cell accumulation in the colon.
© 2024 The Authors. Published by American Chemical Society.

Dabie bandavirus (DBV) is an emerging tick-borne virus that causes severe fever with thrombocytopenia syndrome (SFTS) in infected patients. Human SFTS symptoms progress from fever, fatigue, and muscle pain to the depletion of white blood cells and platelets with fatality rates up to 30%. The recent spread of its vector tick to over 20 states in the United States increases the potential for outbreaks of the SFTS beyond the East Asia. Thus, the development of vaccine to control this rapidly emerging virus is a high priority. In this study, we applied self-assembling ferritin (FT) nanoparticle to enhance the immunogenicity of DBV Gn head domain (GnH) as a vaccine target. Mice immunized with the GnH-FT nanoparticle vaccine induced potent antibody responses and cellular immunity. Immunized aged ferrets were fully protected from the lethal challenge of DBV. Our study describes the GnH-FT nanoparticle vaccine candidate that provides protective immunity against the emerging DBV infection.

Immunometabolism in the tumor microenvironment (TME) and its influence on the immunotherapy response remain uncertain in colorectal cancer (CRC). We perform immunometabolism subtyping (IMS) on CRC patients in the training and validation cohorts. Three IMS subtypes of CRC, namely, C1, C2, and C3, are identified with distinct immune phenotypes and metabolic properties. The C3 subtype exhibits the poorest prognosis in both the training cohort and the in-house validation cohort. The single-cell transcriptome reveals that a S100A9+ macrophage population contributes to the immunosuppressive TME in C3. The dysfunctional immunotherapy response in the C3 subtype can be reversed by combination treatment with PD-1 blockade and an S100A9 inhibitor tasquinimod. Taken together, we develop an IMS system and identify an immune tolerant C3 subtype that exhibits the poorest prognosis. A multiomics-guided combination strategy by PD-1 blockade and tasquinimod improves responses to immunotherapy by depleting S100A9+ macrophages in vivo.
Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.

Hypoxia in tumor microenvironment (TME) represents an obstacle to the efficacy of immunotherapy for pancreatic ductal adenocarcinoma (PDAC) through several aspects such as increasing the expression of immune checkpoints or promoting fibrosis. Reversing hypoxic TME is a potential strategy to improve the validity of immune checkpoint blockade (ICB).
Here, we synthesized polydopamine-nanoparticle-stabilized oxygen microcapsules with excellent stabilization, bioavailability, and biocompatibility for direct oxygen delivery into tumor sites by interfacial polymerization.
We observed oxygen microcapsules enhanced the oxygen concentration in the hypoxia environment and maintained the oxygen concentration for a long period both in vitro and in vivo. We found that oxygen microcapsules could significantly improve the efficiency of ICB against PDAC in vivo. Mechanismly, combined treatments using oxygen microcapsules and ICB could reduce the infiltration of tumor-associated macrophages (TAMs) and polarized pro-tumor M2 macrophages into anti-tumor M1 macrophages. In addition, combined treatments could elevate the proportion of T helper subtype 1 cells (Th1 cells) and cytotoxic T lymphocytes cells (CTLs) to mediate anti-tumor immune response in TME.
In summary, this pre-clinical study indicated that reversing hypoxia in TME by using oxygen microcapsules was an effective strategy to improve the performances of ICB on PDAC, which holds great potential for treating PDAC in the future.
© 2022 The Authors.