Influence of glycosylation on IL-12 family cytokine biogenesis and function.

The interleukin 12 (IL-12) family of cytokines regulates T cell functions and is key for the orchestration of immune responses. Each heterodimeric IL-12 family member is a glycoprotein. However, the impact of glycosylation on biogenesis and function of the different family members has remained incompletely defined. Here, we identify glycosylation sites within human IL-12 family subunits that become modified upon secretion. Building on these insights, we show that glycosylation is dispensable for secretion of human IL-12 family cytokines except for IL-35. Furthermore, our data show that glycosylation differentially influences IL-12 family cytokine functionality, with IL-27 being most strongly affected. Taken together, our study provides a comprehensive analysis of how glycosylation affects biogenesis and function of a key human cytokine family and provides the basis for selectively modulating their secretion via targeting glycosylation.