Sulfated modification can enhance antiviral activities of Achyranthes bidentata polysaccharide against porcine reproductive and respiratory syndrome virus (PRRSV) in vitro

► UV-vis and FT-IR spectrum assays were convenient and efficient to determine the differences of ABPS and sABPS. ► An in vitro assay by MTT method was established to assess the effects of ABPS/sABPS against PRRSV. ► Sulfated ABPS has the potential value to develop a new-type drug against PRRSV infection in the pig industry.