PADI4 and infection: To this end, HFFs were treated with increasing concentrations of the specific inhibitors of the three isoforms (AFM30a for PAD2, HF4 for PAD3, and GSK199 for PAD4) or with equal volumes of vehicle control (DMSO) 1 h before HSV-1 infection (MOI 1) and for the entire duration of the infection.