Most existing vaccines use activators that polarize the immune response to T-helper (Th) 2 response for antibody production. Our positively charged chitosan (Cs)-based nanocomplex (CNC) drives the Th1 response through unknown mechanisms. As receptors for the positively charged CNC are not determined, the physico-chemical properties are hypothesized to correlate with its immunomodulatory effects. To clarify the effects of surface charge and size on the immune response, smaller CNC and negatively charged CNC encapsulating ovalbumin are tested on dendritic cell (DC) 2.4 ​cells. The negatively charged CNC loses activity, but the smaller CNC does not. To further evaluate the material effects, we replace Cs by poly-amino acids. Compared with the negatively charged nanocomplex, the positively charged one preserves its activity. Using immature bone marrow-derived DCs (BMDC) enriched from BALB/c mice as a model to analyze DC differentiation, treatments with positively charged nanocomplexes evidently increase the proportions of Langerin+ dermal DC, CD11blo interstitial DC, and CD8a+ conventional DC. Additionally, vaccination with two doses containing positively charged nanocomplexes are safe and increase ovalbumin-specific IgG and recall T-cell responses in mice. Overall, a positive charge seems to contribute to the immunological effect of nanocomplexes on elevating the Th1 response by modulating DC differentiation.
© 2022 The Authors.

Murine infection models are widely used to study systemic candidiasis caused by C. albicans. Whole-blood models can help to elucidate host-pathogens interactions and have been used for several Candida species in human blood. We adapted the human whole-blood model to murine blood. Unlike human blood, murine blood was unable to reduce fungal burden and more substantial filamentation of C. albicans was observed. This coincided with less fungal association with leukocytes, especially neutrophils. The lower neutrophil number in murine blood only partially explains insufficient infection and filamentation control, as spiking with murine neutrophils had only limited effects on fungal killing. Furthermore, increased fungal survival is not mediated by enhanced filamentation, as a filament-deficient mutant was likewise not eliminated. We also observed host-dependent differences for interaction of platelets with C. albicans, showing enhanced platelet aggregation, adhesion and activation in murine blood. For human blood, opsonization was shown to decrease platelet interaction suggesting that complement factors interfere with fungus-to-platelet binding. Our results reveal substantial differences between murine and human whole-blood models infected with C. albicans and thereby demonstrate limitations in the translatability of this ex vivo model between hosts.
Copyright © 2021 Machata, Sreekantapuram, Hünniger, Kurzai, Dunker, Schubert, Krüger, Schulze-Richter, Speth, Rambach and Jacobsen.

Dendritic cell (DC) aggresome-like induced structures (DALIS) are protein aggregates of polyubiquitylated proteins that form transiently during DC maturation. DALIS scatter randomly throughout the cytosol and serve as antigen storage sites synchronising DC maturation and antigen presentation. Maturation of DCs is accompanied by the induction of the ubiquitin-like modifier FAT10 (also known as UBD), which localises to aggresomes, structures that are similar to DALIS. FAT10 is conjugated to substrate proteins and serves as a signal for their rapid and irreversible degradation by the 26S proteasome similar to, yet independently of ubiquitin, thereby contributing to antigen presentation. Here, we have investigated whether FAT10 is involved in the formation and turnover of DALIS, and whether proteins accumulating in DALIS can be modified through conjunction to FAT10 (FAT10ylated). We found that FAT10 localises to DALIS in maturing DCs and that this localisation occurs independently of its conjugation to substrates. Additionally, we investigated the DALIS turnover in FAT10-deficient and -proficient DCs, and observed FAT10-mediated disassembly of DALIS. Thus, we report further evidence that FAT10 is involved in antigen processing, which may provide a functional rationale as to why FAT10 is selectively induced upon DC maturation.
© 2020. Published by The Company of Biologists Ltd.

Trastuzumab deruxtecan (DS-8201a), a HER2-targeting antibody-drug conjugate with a topoisomerase I inhibitor exatecan derivative (DX-8951 derivative, DXd), has been reported to exert potent antitumor effects in xenograft mouse models and clinical trials. In this study, the immune system-activating ability of DS-8201a was assessed. DS-8201a significantly suppressed tumor growth in an immunocompetent mouse model with human HER2-expressing CT26.WT (CT26.WT-hHER2) cells. Cured immunocompetent mice rejected not only rechallenged CT26.WT-hHER2 cells, but also CT26.WT-mock cells. Splenocytes from the cured mice responded to both CT26.WT-hHER2 and CT26.WT-mock cells. Further analyses revealed that DXd upregulated CD86 expression on bone marrow-derived dendritic cells (DC) in vitro and that DS-8201a increased tumor-infiltrating DCs and upregulated their CD86 expression in vivo DS-8201a also increased tumor-infiltrating CD8+ T cells and enhanced PD-L1 and MHC class I expression on tumor cells. Furthermore, combination therapy with DS-8201a and anti-PD-1 antibody was more effective than either monotherapy. In conclusion, DS-8201a enhanced antitumor immunity, as evidenced by the increased expression of DC markers, augmented expression of MHC class I in tumor cells, and rejection of rechallenged tumor cells by adaptive immune cells, suggesting that DS-8201a enhanced tumor recognition by T cells. Furthermore, DS-8201a treatment benefited from combination with anti-PD-1 antibody, possibly due to increased T-cell activity and upregulated PD-L1 expression induced by DS-8201a. Mol Cancer Ther; 17(7); 1494-503. ©2018 AACR.
©2018 American Association for Cancer Research.

Immune cells are required in the immune response against tumours, although sometimes without success. The present study aimed to investigate dendritic cell (DC) maturation in animals with induced immunosuppression that were subjected to physical activity (PA). Immunosuppression was induced using 7,12-dimethyl-benzanthracene (DMBA). A total of 56 Balb/c mice were divided into four groups, including the control group, non-DMBA administered/PA group (GII), DMBA administered/non-PA group (GIII) and the DMBA administered/PA group (GIV). Bone marrow was removed from the leg bones following sacrifice. Bone marrow-derived DCs were stimulated to differentiate by granulocyte-macrophage colony-stimulating factor, interleukin (IL)-4 and tumour necrosis factor-α, after which the phenotype was assessed by flow cytometry and the cytokine profile was assessed using ELISAs. PA significantly increased the percentage of DCs in GII (55.38±2.63%) and GIV (50.1±3.1%) mice, as compared with GI (34.61±1.28%) and GIII (36.25±1.85%) mice (P<0.05). In addition, GIV mice showed a significantly higher level of cluster of differentiation (CD) 80+/CD86+ DCs (76.38±6.31%), as compared with GI (54.03±6.52%) and GIII (52.07±5.74%) mice (P<0.05). Furthermore, GIV mice showed a significantly higher level of CD80+/major histocompatibility complex class II double labelling (P<0.05), as compared with GIV (95.35±1.22%) and GIII (76.15±5.53%) mice. The expression of interferon-γ was significantly increased in GIV mice [5.89 (5.2-7.12)], as compared with GIII mice [2.75 (1.33-4.4)] (P<0.05). Similarly, the expression of IL-12 was markedly increased in GIV mice [1.27 (0.26-2.57)] compared with GIII mice [0.73 (0.44-1.47)], although the difference was not significant (P=0.063). The results of the present study suggested that PA was able to promote the maturation of DCs and their secretion of anti-tumour cytokines. Therefore, PA may emerge as a tool in immunotherapy.