Inhibition of vertebrate complement system by hematophagous arthropods: inhibitory molecules, mechanisms, physiological roles, and applications

In arthropods,hematophagy has arisen several times throughout evolution.This specialized feeding behavior offered a highly nutritious diet obtained during blood feeds.On the other hand,blood-sucking arthropods must overcome problems brought on by blood intake and digestion.Host blood complement acts on the bite site and is still ac-tive after ingestion,so complement activation is a potential threat to the host's skin feed-ing environment and to the arthropod gut enterocytes.During evolution,blood-sucking arthropods have selected,either in their saliva or gut,anticomplement molecules that inac-tivate host blood complement.This review presents an overview of the complement sys-tem and discusses the arthropod's salivary and gut anticomplement molecules studied to date,exploring their mechanism of action and other aspects related to the arthropod-host-pathogen interface.The possible therapeutic applications of arthropod's anticomplement molecules arealsodiscussed.