Modulation of viral infections by cytokines.

The survival of a host challenged by viral infection depends on many factors. Some are specific, such as antiviral T-cell and B-cell responses. Others are nonspecific, such as intrinsic cellular resistance, macrophage activation, and activation of humoral protective mechanisms (e.g., complement, coagulation, etc.). Cytokines are important mediators and regulators of both types of host response. Furthermore, orchestration of specific humoral and cellular immune responses requires the participation of many cytokines. Details of the complex and overlapping roles that cytokines play in specific immune responses is beyond the scope of this review. Instead, this review will focus on the nonspecific antiviral effects of cytokines.