The enhancement of host defenses against infection--search for the Holy Grail?

With the discovery of new and pharmacologically better described agents, the pursuit of a method for the enhancement of nonspecific host defense against bacterial infection has received a new infusion of interest. Work with the synthetic glycopeptide muramyl dipeptide has indicated its usefulness in a variety of surgically simulated illnesses in experimental animals. The extent of that work is described in detail and current mechanisms of action are explored that focus on the release of transmitter substances from the macrophage, the immediate impact on acute inflammatory cells, and an organ-by-organ dissection of the animal suggesting enhanced containment of experimental infection in animals treated with muramyl dipeptide.