Fresh human CD4 + T cells were isolated from human blood at the Centre for Blood Research, University of British Columbia (UBC) according to the standard protocol using EasySep Direct Human CD4 + T cell isolation kit (STEMCELL). The blood collection protocol was approved by the UBC clinical ethical board (H20-00084) and the blood was collected from consented donors. 100 000 Human CD4 + T cells per well were cultured in 100 µL RPMI 1640 (ThermoFisher) supplemented with 10% fetal bovine serum (FBS) (ThermoFisher) and 1% Penicillin/Streptomycin (P/S) (ThermoFisher). After 24 h, polyanions were added at three different concentrations in triplicates. Further 24 h later, cell toxicity was analyzed with the cell counting kit CCK-8 (Merck) according to the manufacturer's description.