الملخص

The immune system is a complex network of organs containing cells that identify the foreign object in the body. The immune system function is simple yet challenging to eliminate pathogenic agents. Every animal has a rudimentary defensive mechanism against the infections to which they are susceptible. This defense is called innate or natural immunity. No pathogen can infiltrate or attack every organism, even if there are many that have the potential to be harmful. This is because a pathogen can only inflict harm on a susceptible host, and not all species are susceptible to the same pathogens . This review highlights our current understanding of the various immune system components and how they work together to defend the host against pathogens.