Fig. 5: XOs suppress human peripheral blood mononuclear cells and macrophages.

a Human peripheral blood mononuclear cells (PBMCs) were activated with bead-bound CD3/CD28 antibodies in the presence and absence of XOs. b Addition of 20 and 200 μg/mL XOs reduced the count of activated PBMCs from 24,002 ± 6762 to 2342 ± 910 (n = 3; p = 0.029, 3 different donors) and to 2102 ± 1121 (n = 3; p = 0.027, 3 different donors), respectively. To gain more insight into the XOs mechanism of action, cytokine production was evaluated in the PBMCs culture. Addition of XOs reduced the IL-6, TNFα, IL-12p70, and IL-22 production from activated PBMCs. c In the co-cultures of anti-CD3/CD28 activated PBMCs, addition of XOs reduce IL-2, IL-6, IL-10, IL-12p70, IL-22, and TNFα (n = 3, 3 different donors). d XOs suppressed the LPS mediated human macrophages activation. LPS activated NFκB pathway in THP-1 macrophages, and addition of 200 μg/mL of XOs reduces NFκB activation of both 10 ng/mL LPS (n = 4, p = 0.044, 4 biological replicates) and 100 ng/mL LPS (n = 4, p = 0.004, 4 biological replicates) activated THP-1 macrophages. 20 μg/mL of XOs was not enough to interfere with the NFκB activation. XOs influenced the NFκB activation of non-activated THP-1 cells. Addition of 20 μg/mL XOs upregulated the NFκB activity in THP-1 cells from 109 ± 17 to 203 ± 20 (n = 4, p = 0.0117, 4 biological replicates). Furthermore, addition of 200 μg/mL XOs upregulated the NFκB activity in THP-1 cells from 109 ± 17 to 215 ± 23 (n = 4, p = 0.0105, 4 biological replicates). Results are mean ± SD, and statistical significance is calculated through unpaired t-test with Welch’s correction.