Abstract
The human immune system has evolved to cope with various virus infections using two major strategies: host defense and viral tolerance. The host defense relies on the innate and adaptive immune responses to control virus replication, while the viral tolerance allows sufficient virus replication in the host with minimal or no clinical signs. Generally, a balanced host defense and viral tolerance can guarantee health from infections, while disturbed immune homeostasis usually results in diseases. It is desirable to develop drugs/therapeutics to enhance the invulnerability of host immune equilibrium to combat viral infections. In this review, we summarize the advanced understanding on mechanisms of both the host defense against and tolerance to virus infections, and therapeutic agents/approaches that work by modulating the balance between host defense and tolerance.