Human recombinant IL-10 reduces xenogenic cytotoxicity via macrophage M2 polarization.

Xenotransplantation has been considered an alternative to the moderate shortage of donor organs for transplantation. To achieve successful xenotransplatation, there is the need to overcome immune rejection. Although, hyperacute rejection has been overcome by α1,3-galactosyltransferase knockout pig, cellular immune rejection remains as a subsequent barrier. Interleukin-10 (IL-10) is known as an anti-inflammatory and immunomodulatory cytokine which has been shown to limit inflammatory responses by inhibiting macrophage activation in several animal experiments. To study the effect of human IL-10 (hIL-10) on pig-to-human xenotransplantation, porcine kidney epithelial cell line (PK(15)) expressing hIL-10 was established. The cytotoxicity of macrophages decreased by hIL-10 from transgenic cells. Furthermore, there is a decreased production of pro-inflammatory cytokines, tumor necrosis factor-α and interleukin-23, and increased anti-inflammatory cytokines like IL-10, but not transforming growth factor beta, in the presence of hIL-10. Also, macrophage polarization toward M2-like phenotype were induced by hIL-10 from transgenic PK(15) cells. Finally, we suggest that the cytotoxicity of human macrophages was reduced by hIL-10 from transgenic cells, inducing M2-like macrophage polarization. Therefore, these results show that hIL-10 transgenic pig can be used as a model to overcome acute immune rejection in pig-to-human xenotransplantation.