Fig 2: Impact of SCFA application or microbiota suppression on disease development in NZB/WF1 animals. (A) Lupus-prone NZB/WF1 mice were administered antibiotics (ATB) in the drinking water (n = 15–20 mice) versus untreated drinking water (n = 18–20 mice). Overall survival as well as anti-dsDNA autoantibodies and body weight were determined at 28 w. (B–D) Lupus-prone NZB/WF1 mice received a SCFA-mix or untreated drinking water. (B) Overall survival (n SCFA = 27 mice, n untreated = 32 mice), anti-dsDNA autoantibodies, proteinuria and kidney infiltration by leukocytes, as well as spleen weights as sign of lymphoproliferation were determined at 28 w (n SCFA = 17–22 mice, n untreated = 18–24 mice). (C) Body weight (n SCFA=26-29 mice, n untreated = 29 mice), colon length (n SCFA = 18 mice, n untreated = 19 mice) as well as intestinal permeability with FITC-Dextran applied by oral gavage, were determined at 28 w (n SCFA = 5 mice, n untreated = 4 mice; representative of two independent experiments). (D) Broad immune status evaluation in spleen of 28 w old NZB/WF1 mice receiving a SCFA-mix (n = 18) or untreated drinking water (n = 19). Depicted are CD44hi expression on CD4+ and CD8+ as marker of T cell activation as well as frequencies of FoxP3+ Treg and CD103+FoxP3+ effector Treg. The Kaplan–Meier method was used for estimating OS in differently treated groups. All other results are expressed as scatter blots with mean ± SEM; each data point represents an individual mouse; p < 0.05 was considered significant, p > 0.2 is indicated as ns, not significant.

Fig 3: Beta-hydroxybutyrate enhances human T-cell immune capacity during COVID-19. Human peripheral blood mononuclear cells (PBMC) were cultivated for 5 days in RPMI containing 80 mg/dl glucose (NC) and supplemented with 10 mM D/L-beta-hydroxybutyrate (BHB). T-cell stimulation was performed through CD3/CD28 Dynabeads at a bead:cell ratio of 1:8. (A) Flow cytometric quantification of CD8+ T cells expressing intracellular Granzyme B (left), n = 15 individual patients. For better visualization, a histogram example of one patient is shown. (B) Mean fluorescence intensity (MFI) Granzyme B per cell, measured in CD8+ T cells (right), n = 15 individual patients. (C) Protein expression of TNFα/IFNγ/Perforin/Granzyme B in the supernatant of stimulated PBMC, n = 17/14/17/18 individual patients. (D) Relative CD8+ cell lysis activity as measured by calcein-fluorescence of isolated CD8+ T cells, n = 8 individual patients. Paired t-test or Wilcoxon matched-pairs signed rank test, as appropriate. *p < 0.05, **p < 0.01.

Fig 4: Induction of efficient tumor control in a CT26 colon cancer mouse model immunized with a long RNF10 uPeptide vaccine(A) Tumor growth (mean ± SEM) in untreated (control) or RNF10-uPeptide immunized BALB/C mice (n = 7), inoculated subcutaneously (s.c.) with CT26 cells. (B) Upper panel, CD8-stained cancer tissue sections. Scale bar, 20 μm. Lower panel, proportional CD8+ lymphocyte areas in tumor tissue of control (n = 5) or vaccinated (n = 5) animals. (C) Tumor-infiltrating lymphocytes (TILs) or splenocytes were stimulated with PMA and ionomycin to assess the ability of CD8+ T cells to produce IFN-γ and TNF-α. Cytokine production was determined by intracellular cytokine staining and flow cytometry. Data are representative of two independent experiments. Percentages of dead tumor cells are shown (mean ± SD, n = 3). ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, compared with untreated T cells (−). p-values were determined by two-tailed one-way ANOVA with Dunnett’s multiple-comparisons test.