TLR3 and infection: As the major targeted cell type, macrophages were also found to produce type I IFNs in mice during infection with a non-metastatic Leishmania species L. major [147] and metastatic L. guyanensis [148], the latter of which was dependent on the TLR3-TRIF signaling pathway by recognizing parasite-derived factors, including dsRNA Leishmania RNA virus 1 (LRV1).