The human immune system is one of the main host defence mechanism against infections, initiating a complex response when confronted with pathogenic invaders. This response involves pathogen recognition, initiation of transcription of genes important for host defence, production of cytokines and defensins, activation of phagocytosis, and later, the initiation of adaptive immune responses. Typically, the interaction between pathogen and host results in acute and transient inflammation, with the symptoms subsiding once the pathogen has been cleared.
