Figure 1.

General viral strategies to manipulate innate PRR to enhance virus entry. Viruses may express glycosylated surface proteins which do not allow collectin binding, such as MBL, and subsequent complement-mediated destruction (1). Alternatively, viruses may benefit from SP-A recognition to improve cell entry, through unknown mechanism (2). Viruses may directly bind several different endocytic/phagocytic PRRs (SR, MR, DC-SIGN) to usurp intracellular routes for efficient entry (3). Virus binding to TLR (4) may also promote specific virus receptor (VR) expression (5) to enhance further virus entry (6). Finally, co-infecting bacteria may contribute to virus entry via TLR signaling (7) through still undefined process (8).