ABSTRACTNitric oxide is produced in high amount from the break down of arginine by a group of enzyme called nitric oxide synthase. Nitric oxide is an intercellular messenger that has been recognized as one of the versatile player in the immune system. Cells of the innate immune system such as macrophages, neutrophil and natural killer use patterns recognition receptors to recognize the molecular patters associated with pathogens. The specific role nitric oxide plays depend on the place o...