Major pathways of macrophage activation

There are two major pathways of macrophage activation, called classical macrophage activation and alternative macrophage activation including the following:

classical macrophage activation: classical macrophage activation may be induced by microbial products such as endotoxin.classical activated macrophages produce NO and ROS an upregulate lysosomal enzymes all of which enhance their ability to kill ingested organism and secret cytokines that stimulate inflammation. This macrophage are important in host defence against microbes and in many inflammatory reactions.

alternative macrophage activation: alternative macrophage activation is induced by cytokines other than IFN Gamma such as interleukin-4, interleukin-13 produced by T Lymphocytes and other cell. The principal function of alternative activated macrophages is in tissue repair. They secrete growth factor that promote angiogenesis. And aslo, it is and important in tissue repair and the resolution of information.