Role of Cytokines in the Prevention and Treatment of Mastitis
The response of humans and most domestic animals to any pathogen involves a complex interactive cellular network directed at protecting the host and eliminating the pathogen. In the acute phase, the primary mediators of this defense mechanism are phagocytic cells (polymorphonuclear cells, monocytes, tissue macrophages). These cells engulf or phagocytose pathogens and are subsequently activated to destroy the pathogen primarily through enzymatic degradation (peptidase, mucopeptidose, phosphatase, etc.), pH, and/or generation of free oxygen radicals. Accordingly there appear to be distinct cytokines associated with the acute phase of the host response (1-3). If the pathogen persists, then a second series of functionally distinct cells are induced within the continuum of the hosts’ response to the pathogen, and accordingly, a distinct profile of cytokines is elicited that modulate this response (4-6). The hallmark of this second-phase response to a chronic infection is the activation of the immune system. The unique features of the immune system are the exquisite specificity of recognition, diversity and adaptive nature of the response, and memory of previous encounters with pathogens. Once elicited, the immune response through a variety 390of mediators also can interact with components of an acute response by expanding the number, as well as the efficiency, of the phagocytic cells. There By, the response to acute and chronic infections operate in concert to effectively keep the host disease-free.