Infectious disease remains an ever-growing health concern worldwide due to increasing antibiotic-resistant microbial strains, immune-compromised populations, international traffic and globalisation, and bioterrorism. There exists an urgent need to develop novel prophylactic and therapeutic strategies. In addition to classic antibiotic therapeutics, immune-modulatory molecules such as cytokines or their inhibitors represent a promising form of antimicrobial therapeutics or immune adjuvant used for the purpose of vaccination. These molecules, in the form of either recombinant protein or transgene, exert their antimicrobial effect by enhancing infectious agent-specific immune activation or memory development, or by dampening undesired inflammatory and immune responses resulting from infection and host defence mechanisms. In the last two decades, a number of cytokine therapy-based experimental and clinical trials have been conducted, and some of these efforts have led to the routine clinical use of cytokines. For instance, although IFNs have been used to treat hepatitis C with great success, many other cytokines are yet to be fully evaluated for their antimicrobial potential. This review discusses the biology and therapeutic potential of selected immune modulatory cytokines and their inhibitors, including granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, IFN-gamma, IL-12 and TNF.
