Language of the Immune System
The immune system has elegantly evolved through centuries of human generations to a highly conserved set of cells that fulfill communications and execution roles through signaling molecules that are collectively referred to as mediators. The key players of the immune system remain the same across body sites and even across other species in the kingdom. What changes is the level of activation of different cell types in response to the environmental signals present within each unique system. For instance, due to the presence of teeth and the underlying supporting bone, the manifestation of inflammatory disease in the oral periodontal mucosa is fundamentally different to inflammation in the adjacent esophageal mucosa. Nonetheless, in both cases it is primarily driven by the same non-specific response cells that collective compose the innate immune system, which is a first line of response to pathogens and danger signals. Once the initial response is mounted, then specialized cells that belong to the adaptive system are signaled and become trained to the specific environmental trigger. The remainder of the chapter will delineate the key players that together form the immune system and discuss their roles in oral inflammation.