Human primary CD4 + T cells were cultivated in RPMI 1640 + 10% FBS + 1% P/S. The cells were seeded at 80 000 cells per well in 100 µL in a 96 well plate and then activated for cytokine secretion with a cell stimulation cocktail (PMA 100 ng/mL; ionomycin 1 µg/mL) from ThermoFisher and 50 ng/mL TSLP (PeproTech). Polyanions as potential inhibitors of activation were then added to the wells and IL-13 levels were determined after 36 h by ELISA as a readout. To determine the difference in STAT6 phosphorylation state, cells were lyzed 20 mins after adding the cytokines and inhibitors.