Central Nervous System Diseases and Inflammation.

The immune system has evolved numerous mechanisms to protect the host against perceived danger, as well as regulatory mechanisms for the resolution of inflammation and/or repair of the host. While the adaptive immune responses that include specific antibody and T cells are critical in eliminating many pathogenic organisms, the first immune responses are provided by the innate immune system. This immediate response is critical in assessing the level of "danger" or injury and consequently directing the subsequent recruitment of other immune system components. These responses are rapid, and include both cellular elements (phagocytic cells, natural killer cells) and protein elements (the complement system, defensins). Some components of the host response to danger if insufficiently regulated can result excessive inflammation and tissue damage including neurotoxicity in the central nervous system (CNS). Thus, a balance between generating a toxic environment for pathogens while providing reparative functions to the tissues must be maintained, and thus requires monitoring systems and appropriate modulation of immune response mediators. This is certainly the case for the generally proinflammatory complement cascade, a powerful effective mechanism of the immune system. [ABSTRACT FROM AUTHOR]