Figure 3.

Novel fusion cytokine IL233 bearing IL-2 and IL-33 activities in one molecule offers better protection than IL-2 and IL-33 used as a mixture. (A) Schematic representation of IL233 fusion cytokine consisting of IL-2 aa residues 21–169 joined via a 15-aa linker (GGGGS)₃ to the C-terminal cytokine domain of IL-33 (aa residues 109–266). (B) Mice were injected with 66 pmol per mouse per day with a mixture of IL-2 and IL-33 or IL233 for 5 days, and mice were analyzed on day 8. IL233 was better than equimolar doses of IL-2 and IL-33 injected as a mixture in increasing Tregs in blood and spleen (C), measured as proportion of CD4⁺Foxp3⁺ cells in the CD4⁺ T cell gate. (D) Absolute number of Tregs per spleen in mice was also higher in mice treated with IL233. (E) Mice were pretreated with saline or IL233 or a mixture of IL-2 and IL-33 at two different doses (22 or 66 pmol, administered intraperitoneally) daily for five consecutive days before subjecting them to 26 minutes of bilateral ischemia. Mice were euthanized after 24 hours of reperfusion, and PCr (F) and ATN scores (G) show that the mixture of IL-2 and IL-33 at a dose of 22 pmol was unable to restrict renal dysfunction and injury, whereas an equimolar dose of IL233 completely preserved renal structure and function. Symbols represent individual mice; mean±SEM is shown (n≥5). *P<0.05; **P<0.01; ***P<0.001.