Regulating the balance of Th17/Treg cells in gut-lung axis contributed to the therapeutic effect of Houttuynia cordata polysaccharides on H1N1-induced acute lung injury.

Our previous study had demonstrated that oral administration of Houttuynia cordata polysaccharides (HCP) without in vitro antiviral activity ameliorated gut and lung injuries induced by influenza A virus (IAV) in mice. However, as macromolecules, HCP was hard to be absorbed in gastrointestinal tract and had no effect on lung injury when administrated intravenously. The action mechanism of HCP was thus proposed as regulating the gut mucosal-associated lymphoid tissue (GALT).