Progress in Antiviral Innate Immunity

Viruses are small infectious particles that only replicate inside the living cells of the hosts. When infected by viruses,the immune system of the hosts will be activated to defense against these invaders. In vertebrates, there are two immune systems, the adaptive immune system and the innate immune system. While the adaptive immune system is composed of highly specialized, systemic cells and processes that eliminate or prevent pathogen growth, the innate immune system defends the host from virus infection through widely expressed pattern recognition receptors and rapid production of downstream cytokines. Being the first line of the host defense and the prerequisite of adaptive immunity, the innate immune system plays a significant role in antiviral immune responses.