In the study presented here, we discovered strong interactions of polyglycerol sulfates with the type 2 inflammation-driving factors thymic stromal lymphopoietin (TSLP) and fibronectin (FN), leading to anti-inflammatory effects on the TSLP-mediated TH2-polarization of CD4 + T cells and on the FN-mediated inflammation in inflamed bronchial epithelium models. A detailed analysis of the polyglycerol anions' binding behavior suggested that polymer architecture is not essential to its binding to FN, while linear polymers can bind to TSLP more effectively than their dendritic counterparts. The inquiry into the impact of polyglycerol sulfates' size on their affinity to TSLP showed only minor effects, with dPGS10 and dPGS50 showing the strongest affinity, while dPGS100 exhibited slightly reduced binding. Sulfate groups, on the other hand, proved essential to the polyanions' interaction with both proteins; functionalization with carboxylate groups prevented significant interaction from occurring. This result echoes previous findings on the essential role of sulfates in binding to heparin binding proteins, in particular P-and L-selectin. Having established the importance of sulfate groups, we found that a high degree of sulfate functionalization was necessary: reducing the functionalization degree from 90 % to 40 % led to a 5000-fold weaker binding to FN, confirming charge-charge interactions as the driving force. Previous literature also describes a role for hydrophobic interactions in protein binding of heparin, an effect that could also be considered in the development of further specialized TSLP or FN binders. In addition, HS significantly reduced IL-13 at concentrations as low as 1 ng/mL. This high potency was initially surprising, since heparin showed markedly stronger interaction in the binding assay and a lower potency of IL-13 reduction. We believe that this result is attributable to the highly stable complexes formed between TSLP and HS, since its dissociation constant kd is an order of magnitude smaller than that of TSLP to heparin (Table ). The interaction of HS or heparin with other proteins is also likely, since both are known to bind to numerous additional proteins.