Dermacentor variabilis: Regulation of Macrophage Migration and Phagocytosis by Tick Saliva

Abstract

We studied the effects of tick saliva and salivary gland extract (SGX) on cell migration, cell signaling, and phagocytosis in the murine macrophage cell line, IC‐21. Saliva increased both basal and platelet‐derived growth factor (PDGF)‐stimulated macrophage migration. However, saliva did not affect PDGF‐stimulated extracellular signal‐regulated kinase (ERK) or AKT (protein kinase B) activity. Saliva also had no affect on phorbol‐12‐myristate‐13‐acetate (PMA)‐stimulated AKT activity. Lipopolysaccharide (LPS)‐stimulated Interleukin 1 receptor‐associated kinase (IRAK) activity was unaffected by SGX, while zymosan‐mediated IRAK activity increased when cells were pretreated with saliva. Saliva suppressed phagocytosis of zymosan particles by macrophages. These results suggest that Dermacentor variabilis has evolved a mechanism for selectively controlling the host's wound healing response.