MAPKAPK2 and Recurrent upper respiratory tract infections: This mechanism is illustrated by HAdV type C serotypes associated with relatively mild self-limiting upper respiratory tract infections (e.g., HAdV-C2 and HAdV-C5), which are known to trigger transient activation of p38-MAPK and its downstream target MAPKAP kinase 2 (MK2) during early stages of cell penetration (Horwitz, 1995; Suomalainen et al., 2001).