ABSTRACT
There are many molecules of the innate immune system which are important in mediating protection against microbes during the period before the development of adaptive immunity. Although some of these molecules react with particular microbial structures, they are nonspecific in that they can react with many different microbes that express these structures. These molecules include the antimicrobial peptides, complement proteins, acute phase proteins, and interferons. Many of the molecules involved in innate immunity are also associated with adaptive immunity. Thus, the complement system can be activated through antibodies, and cytokines are involved in activation of antigen-presenting cells critical to triggering T-lymphocyte responses. Cytokines released by macrophages also play a role in acute inflammation. Thus, the immune response to microbes is continuous with both systems being intimately involved and synergistic.
