Innate Immune Response

The immune system serves to defend against pathogens: microorganisms that attempt to invade and cause disease in a host.

The innate immune response has physical and chemical barriers that exist as the first line of defense against infectious pathogens.

Upon pathogen entry to the body, the innate immune system uses several mechanisms to destroy the pathogen and any cells it has infected.

Natural killer cells are part of the innate immune response that recognize abnormal MHC I molecules on infected/tumor cells and kill them.

Around 20 soluble proteins comprise the complement system, which helps destroy extracellular microorganisms that have invaded the body.