TLR9 and infection: Endosomal DNA-sensor Toll-like receptor (TLR)-9 has been shown to recognize microbial DNA and induces the host defense against infections (Kawai and Akira, 2010), such as Human cytomegalovirus (HCMV), Herpes simplex virus (HSV)-1 (Hochrein et al., 2004) and HSV-2 (Lund et al., 2003).