Proteases in Pathogen and Host: Their Significance in Inflammation and Infection – GRK-PRO

Infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce. Infectious disease, also known as transmissible disease or communicable disease, is illness resulting from an infection.

Inflammation (from Latin: inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molecular mediators. The function of inflammation is to eliminate the initial cause of cell injury, clear out necrotic cells and tissues damaged from the original insult and the inflammatory process, and initiate tissue repair.

In biology, a pathogen (Greek: πάθος pathos "suffering, passion" and -γενής -genēs "producer of") or a germ in the oldest and broadest sense is anything that can produce disease; the term came into use in the 1880s. Typically the term is used to describe an infectious agent such as a virus, bacterium, protozoa, prion, a fungus, or other micro-organism. The scientific study of pathogens is called Pathology.