Further in vitro study in the RAW246.7 macrophage cell line identified that PD-L1 was stimulated by the adult antigens of C. hepatica only on the M1 macrophages, while PD-L2 was induced by the egg antigens on the M2 macrophages, which is correlated with the in vivo infection course of C. hepatica. The gene discussed is PDCD1LG2; the disease is infection.